diff --git a/Documentation/config/promisor.adoc b/Documentation/config/promisor.adoc
index 98c5cb2ec2..9192acfd24 100644
--- a/Documentation/config/promisor.adoc
+++ b/Documentation/config/promisor.adoc
@@ -1,3 +1,30 @@
 promisor.quiet::
 	If set to "true" assume `--quiet` when fetching additional
 	objects for a partial clone.
+
+promisor.advertise::
+	If set to "true", a server will use the "promisor-remote"
+	capability, see linkgit:gitprotocol-v2[5], to advertise the
+	promisor remotes it is using, if it uses some. Default is
+	"false", which means the "promisor-remote" capability is not
+	advertised.
+
+promisor.acceptFromServer::
+	If set to "all", a client will accept all the promisor remotes
+	a server might advertise using the "promisor-remote"
+	capability. If set to "knownName" the client will accept
+	promisor remotes which are already configured on the client
+	and have the same name as those advertised by the client. This
+	is not very secure, but could be used in a corporate setup
+	where servers and clients are trusted to not switch name and
+	URLs. If set to "knownUrl", the client will accept promisor
+	remotes which have both the same name and the same URL
+	configured on the client as the name and URL advertised by the
+	server. This is more secure than "all" or "knownName", so it
+	should be used if possible instead of those options. Default
+	is "none", which means no promisor remote advertised by a
+	server will be accepted. By accepting a promisor remote, the
+	client agrees that the server might omit objects that are
+	lazily fetchable from this promisor remote from its responses
+	to "fetch" and "clone" requests from the client. See
+	linkgit:gitprotocol-v2[5].
diff --git a/Documentation/gitprotocol-v2.adoc b/Documentation/gitprotocol-v2.adoc
index 9f6350bbf2..5598c93e67 100644
--- a/Documentation/gitprotocol-v2.adoc
+++ b/Documentation/gitprotocol-v2.adoc
@@ -785,6 +785,60 @@ retrieving the header from a bundle at the indicated URI, and thus
 save themselves and the server(s) the request(s) needed to inspect the
 headers of that bundle or bundles.
 
+promisor-remote=<pr-infos>
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The server may advertise some promisor remotes it is using or knows
+about to a client which may want to use them as its promisor remotes,
+instead of this repository. In this case <pr-infos> should be of the
+form:
+
+	pr-infos = pr-info | pr-infos ";" pr-info
+
+	pr-info = "name=" pr-name | "name=" pr-name "," "url=" pr-url
+
+where `pr-name` is the urlencoded name of a promisor remote, and
+`pr-url` the urlencoded URL of that promisor remote.
+
+In this case, if the client decides to use one or more promisor
+remotes the server advertised, it can reply with
+"promisor-remote=<pr-names>" where <pr-names> should be of the form:
+
+	pr-names = pr-name | pr-names ";" pr-name
+
+where `pr-name` is the urlencoded name of a promisor remote the server
+advertised and the client accepts.
+
+Note that, everywhere in this document, `pr-name` MUST be a valid
+remote name, and the ';' and ',' characters MUST be encoded if they
+appear in `pr-name` or `pr-url`.
+
+If the server doesn't know any promisor remote that could be good for
+a client to use, or prefers a client not to use any promisor remote it
+uses or knows about, it shouldn't advertise the "promisor-remote"
+capability at all.
+
+In this case, or if the client doesn't want to use any promisor remote
+the server advertised, the client shouldn't advertise the
+"promisor-remote" capability at all in its reply.
+
+The "promisor.advertise" and "promisor.acceptFromServer" configuration
+options can be used on the server and client side to control what they
+advertise or accept respectively. See the documentation of these
+configuration options for more information.
+
+Note that in the future it would be nice if the "promisor-remote"
+protocol capability could be used by the server, when responding to
+`git fetch` or `git clone`, to advertise better-connected remotes that
+the client can use as promisor remotes, instead of this repository, so
+that the client can lazily fetch objects from these other
+better-connected remotes. This would require the server to omit in its
+response the objects available on the better-connected remotes that
+the client has accepted. This hasn't been implemented yet though. So
+for now this "promisor-remote" capability is useful only when the
+server advertises some promisor remotes it already uses to borrow
+objects from.
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/large-object-promisors.adoc b/Documentation/technical/large-object-promisors.adoc
new file mode 100644
index 0000000000..dea8dafa66
--- /dev/null
+++ b/Documentation/technical/large-object-promisors.adoc
@@ -0,0 +1,656 @@
+Large Object Promisors
+======================
+
+Since Git has been created, users have been complaining about issues
+with storing large files in Git. Some solutions have been created to
+help, but they haven't helped much with some issues.
+
+Git currently supports multiple promisor remotes, which could help
+with some of these remaining issues, but it's very hard to use them to
+help, because a number of important features are missing.
+
+The goal of the effort described in this document is to add these
+important features.
+
+We will call a "Large Object Promisor", or "LOP" in short, a promisor
+remote which is used to store only large blobs and which is separate
+from the main remote that should store the other Git objects and the
+rest of the repos.
+
+By extension, we will also call "Large Object Promisor", or LOP, the
+effort described in this document to add a set of features to make it
+easier to handle large blobs/files in Git by using LOPs.
+
+This effort aims to especially improve things on the server side, and
+especially for large blobs that are already compressed in a binary
+format.
+
+This effort aims to provide an alternative to Git LFS
+(https://git-lfs.com/) and similar tools like git-annex
+(https://git-annex.branchable.com/) for handling large files, even
+though a complete alternative would very likely require other efforts
+especially on the client side, where it would likely help to implement
+a new object representation for large blobs as discussed in:
+
+https://lore.kernel.org/git/xmqqbkdometi.fsf@gitster.g/
+
+0) Non goals
+------------
+
+- We will not discuss those client side improvements here, as they
+  would require changes in different parts of Git than this effort.
++
+So we don't pretend to fully replace Git LFS with only this effort,
+but we nevertheless believe that it can significantly improve the
+current situation on the server side, and that other separate
+efforts could also improve the situation on the client side.
+
+- In the same way, we are not going to discuss all the possible ways
+  to implement a LOP or their underlying object storage, or to
+  optimize how LOP works.
++
+Our opinion is that the simplest solution for now is for LOPs to use
+object storage through a remote helper (see section II.2 below for
+more details) to store their objects. So we consider that this is the
+default implementation. If there are improvements on top of this,
+that's great, but our opinion is that such improvements are not
+necessary for LOPs to already be useful. Such improvements are likely
+a different technical topic, and can be taken care of separately
+anyway.
++
+So in particular we are not going to discuss pluggable ODBs or other
+object database backends that could chunk large blobs, dedup the
+chunks and store them efficiently. Sure, that would be a nice
+improvement to store large blobs on the server side, but we believe
+it can just be a separate effort as it's also not technically very
+related to this effort.
++
+We are also not going to discuss data transfer improvements between
+LOPs and clients or servers. Sure, there might be some easy and very
+effective optimizations there (as we know that objects on LOPs are
+very likely incompressible and not deltifying well), but this can be
+dealt with separately in a separate effort.
+
+In other words, the goal of this document is not to talk about all the
+possible ways to optimize how Git could handle large blobs, but to
+describe how a LOP based solution can already work well and alleviate
+a number of current issues in the context of Git clients and servers
+sharing Git objects.
+
+Even if LOPs are used not very efficiently, they can still be useful
+and worth using in some cases, as we will see in more details
+later in this document:
+
+  - they can make it simpler for clients to use promisor remotes and
+    therefore avoid fetching a lot of large blobs they might not need
+    locally,
+
+  - they can make it significantly cheaper or easier for servers to
+    host a significant part of the current repository content, and
+    even more to host content with larger blobs or more large blobs
+    than currently.
+
+I) Issues with the current situation
+------------------------------------
+
+- Some statistics made on GitLab repos have shown that more than 75%
+  of the disk space is used by blobs that are larger than 1MB and
+  often in a binary format.
+
+- So even if users could use Git LFS or similar tools to store a lot
+  of large blobs out of their repos, it's a fact that in practice they
+  don't do it as much as they probably should.
+
+- On the server side ideally, the server should be able to decide for
+  itself how it stores things. It should not depend on users deciding
+  to use tools like Git LFS on some blobs or not.
+
+- It's much more expensive to store large blobs that don't delta
+  compress well on regular fast seeking drives (like SSDs) than on
+  object storage (like Amazon S3 or GCP Buckets). Using fast drives
+  for regular Git repos makes sense though, as serving regular Git
+  content (blobs containing text or code) needs drives where seeking
+  is fast, but the content is relatively small. On the other hand,
+  object storage for Git LFS blobs makes sense as seeking speed is not
+  as important when dealing with large files, while costs are more
+  important. So the fact that users don't use Git LFS or similar tools
+  for a significant number of large blobs has likely some bad
+  consequences on the cost of repo storage for most Git hosting
+  platforms.
+
+- Having large blobs handled in the same way as other blobs and Git
+  objects in Git repos instead of on object storage also has a cost in
+  increased memory and CPU usage, and therefore decreased performance,
+  when creating packfiles. (This is because Git tries to use delta
+  compression or zlib compression which is unlikely to work well on
+  already compressed binary content.) So it's not just a storage cost
+  increase.
+
+- When a large blob has been committed into a repo, it might not be
+  possible to remove this blob from the repo without rewriting
+  history, even if the user then decides to use Git LFS or a similar
+  tool to handle it.
+
+- In fact Git LFS and similar tools are not very flexible in letting
+  users change their minds about the blobs they should handle or not.
+
+- Even when users are using Git LFS or similar tools, they are often
+  complaining that these tools require significant effort to set up,
+  learn and use correctly.
+
+II) Main features of the "Large Object Promisors" solution
+----------------------------------------------------------
+
+The main features below should give a rough overview of how the
+solution may work. Details about needed elements can be found in
+following sections.
+
+Even if each feature below is very useful for the full solution, it is
+very likely to be also useful on its own in some cases where the full
+solution is not required. However, we'll focus primarily on the big
+picture here.
+
+Also each feature doesn't need to be implemented entirely in Git
+itself. Some could be scripts, hooks or helpers that are not part of
+the Git repo. It would be helpful if those could be shared and
+improved on collaboratively though. So we want to encourage sharing
+them.
+
+1) Large blobs are stored on LOPs
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Large blobs should be stored on special promisor remotes that we will
+call "Large Object Promisors" or LOPs. These LOPs should be additional
+remotes dedicated to contain large blobs especially those in binary
+format. They should be used along with main remotes that contain the
+other objects.
+
+Note 1
+++++++
+
+To clarify, a LOP is a normal promisor remote, except that:
+
+- it should store only large blobs,
+
+- it should be separate from the main remote, so that the main remote
+  can focus on serving other objects and the rest of the repos (see
+  feature 4) below) and can use the LOP as a promisor remote for
+  itself.
+
+Note 2
+++++++
+
+Git already makes it possible for a main remote to also be a promisor
+remote storing both regular objects and large blobs for a client that
+clones from it with a filter on blob size. But here we explicitly want
+to avoid that.
+
+Rationale
++++++++++
+
+LOPs aim to be good at handling large blobs while main remotes are
+already good at handling other objects.
+
+Implementation
+++++++++++++++
+
+Git already has support for multiple promisor remotes, see
+link:partial-clone.html#using-many-promisor-remotes[the partial clone documentation].
+
+Also, Git already has support for partial clone using a filter on the
+size of the blobs (with `git clone --filter=blob:limit=<size>`).  Most
+of the other main features below are based on these existing features
+and are about making them easy and efficient to use for the purpose of
+better handling large blobs.
+
+2) LOPs can use object storage
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+LOPs can be implemented using object storage, like an Amazon S3 or GCP
+Bucket or MinIO (which is open source under the GNU AGPLv3 license) to
+actually store the large blobs, and can be accessed through a Git
+remote helper (see linkgit:gitremote-helpers[7]) which makes the
+underlying object storage appear like a remote to Git.
+
+Note
+++++
+
+A LOP can be a promisor remote accessed using a remote helper by
+both some clients and the main remote.
+
+Rationale
++++++++++
+
+This looks like the simplest way to create LOPs that can cheaply
+handle many large blobs.
+
+Implementation
+++++++++++++++
+
+Remote helpers are quite easy to write as shell scripts, but it might
+be more efficient and maintainable to write them using other languages
+like Go.
+
+Some already exist under open source licenses, for example:
+
+  - https://github.com/awslabs/git-remote-s3
+  - https://gitlab.com/eric.p.ju/git-remote-gs
+
+Other ways to implement LOPs are certainly possible, but the goal of
+this document is not to discuss how to best implement a LOP or its
+underlying object storage (see the "0) Non goals" section above).
+
+3) LOP object storage can be Git LFS storage
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The underlying object storage that a LOP uses could also serve as
+storage for large files handled by Git LFS.
+
+Rationale
++++++++++
+
+This would simplify the server side if it wants to both use a LOP and
+act as a Git LFS server.
+
+4) A main remote can offload to a LOP with a configurable threshold
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+On the server side, a main remote should have a way to offload to a
+LOP all its blobs with a size over a configurable threshold.
+
+Rationale
++++++++++
+
+This makes it easy to set things up and to clean things up. For
+example, an admin could use this to manually convert a repo not using
+LOPs to a repo using a LOP. On a repo already using a LOP but where
+some users would sometimes push large blobs, a cron job could use this
+to regularly make sure the large blobs are moved to the LOP.
+
+Implementation
+++++++++++++++
+
+Using something based on `git repack --filter=...` to separate the
+blobs we want to offload from the other Git objects could be a good
+idea. The missing part is to connect to the LOP, check if the blobs we
+want to offload are already there and if not send them.
+
+5) A main remote should try to remain clean from large blobs
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A main remote should try to avoid containing a lot of oversize
+blobs. For that purpose, it should offload as needed to a LOP and it
+should have ways to prevent oversize blobs to be fetched, and also
+perhaps pushed, into it.
+
+Rationale
++++++++++
+
+A main remote containing many oversize blobs would defeat the purpose
+of LOPs.
+
+Implementation
+++++++++++++++
+
+The way to offload to a LOP discussed in 4) above can be used to
+regularly offload oversize blobs. About preventing oversize blobs from
+being fetched into the repo see 6) below. About preventing oversize
+blob pushes, a pre-receive hook could be used.
+
+Also there are different scenarios in which large blobs could get
+fetched into the main remote, for example:
+
+- A client that doesn't implement the "promisor-remote" protocol
+  (described in 6) below) clones from the main remote.
+
+- The main remote gets a request for information about a large blob
+  and is not able to get that information without fetching the blob
+  from the LOP.
+
+It might not be possible to completely prevent all these scenarios
+from happening. So the goal here should be to implement features that
+make the fetching of large blobs less likely. For example adding a
+`remote-object-info` command in the `git cat-file --batch` protocol
+and its variants might make it possible for a main repo to respond to
+some requests about large blobs without fetching them.
+
+6) A protocol negotiation should happen when a client clones
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When a client clones from a main repo, there should be a protocol
+negotiation so that the server can advertise one or more LOPs and so
+that the client and the server can discuss if the client could
+directly use a LOP the server is advertising. If the client and the
+server can agree on that, then the client would be able to get the
+large blobs directly from the LOP and the server would not need to
+fetch those blobs from the LOP to be able to serve the client.
+
+Note
+++++
+
+For fetches instead of clones, a protocol negotiation might not always
+happen, see the "What about fetches?" FAQ entry below for details.
+
+Rationale
++++++++++
+
+Security, configurability and efficiency of setting things up.
+
+Implementation
+++++++++++++++
+
+A "promisor-remote" protocol v2 capability looks like a good way to
+implement this. The way the client and server use this capability
+could be controlled by configuration variables.
+
+Information that the server could send to the client through that
+protocol could be things like: LOP name, LOP URL, filter-spec (for
+example `blob:limit=<size>`) or just size limit that should be used as
+a filter when cloning, token to be used with the LOP, etc.
+
+7) A client can offload to a LOP
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When a client is using a LOP that is also a LOP of its main remote,
+the client should be able to offload some large blobs it has fetched,
+but might not need anymore, to the LOP.
+
+Note
+++++
+
+It might depend on the context if it should be OK or not for clients
+to offload large blobs they have created, instead of fetched, directly
+to the LOP without the main remote checking them in some ways
+(possibly using hooks or other tools).
+
+This should be discussed and refined when we get closer to
+implementing this feature.
+
+Rationale
++++++++++
+
+On the client, the easiest way to deal with unneeded large blobs is to
+offload them.
+
+Implementation
+++++++++++++++
+
+This is very similar to what 4) above is about, except on the client
+side instead of the server side. So a good solution to 4) could likely
+be adapted to work on the client side too.
+
+There might be some security issues here, as there is no negotiation,
+but they might be mitigated if the client can reuse a token it got
+when cloning (see 6) above). Also if the large blobs were fetched from
+a LOP, it is likely, and can easily be confirmed, that the LOP still
+has them, so that they can just be removed from the client.
+
+III) Benefits of using LOPs
+---------------------------
+
+Many benefits are related to the issues discussed in "I) Issues with
+the current situation" above:
+
+- No need to rewrite history when deciding which blobs are worth
+  handling separately than other objects, or when moving or removing
+  the threshold.
+
+- If the protocol between client and server is developed and secured
+  enough, then many details might be setup on the server side only and
+  all the clients could then easily get all the configuration
+  information and use it to set themselves up mostly automatically.
+
+- Storage costs benefits on the server side.
+
+- Reduced memory and CPU needs on main remotes on the server side.
+
+- Reduced storage needs on the client side.
+
+IV) FAQ
+-------
+
+What about using multiple LOPs on the server and client side?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+That could perhaps be useful in some cases, but for now it's more
+likely that in most cases a single LOP will be advertised by the
+server and should be used by the client.
+
+A case where it could be useful for a server to advertise multiple
+LOPs is if a LOP is better for some users while a different LOP is
+better for other users. For example some clients might have a better
+connection to a LOP than others.
+
+In those cases it's the responsibility of the server to have some
+documentation to help clients. It could say for example something like
+"Users in this part of the world might want to pick only LOP A as it
+is likely to be better connected to them, while users in other parts
+of the world should pick only LOP B for the same reason."
+
+When should we trust or not trust the LOPs advertised by the server?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In some contexts, like in corporate setup where the server and all the
+clients are parts of an internal network in a company where admins
+have all the rights on every system, it's OK, and perhaps even a good
+thing, if the clients fully trust the server, as it can help ensure
+that all the clients are on the same page.
+
+There are also contexts in which clients trust a code hosting platform
+serving them some repos, but might not fully trust other users
+managing or contributing to some of these repos. For example, the code
+hosting platform could have hooks in place to check that any object it
+receives doesn't contain malware or otherwise bad content. In this
+case it might be OK for the client to use a main remote and its LOP if
+they are both hosted by the code hosting platform, but not if the LOP
+is hosted elsewhere (where the content is not checked).
+
+In other contexts, a client should just not trust a server.
+
+So there should be different ways to configure how the client should
+behave when a server advertises a LOP to it at clone time.
+
+As the basic elements that a server can advertise about a LOP are a
+LOP name and a LOP URL, the client should base its decision about
+accepting a LOP on these elements.
+
+One simple way to be very strict in the LOP it accepts is for example
+for the client to check that the LOP is already configured on the
+client with the same name and URL as what the server advertises.
+
+In general default and "safe" settings should require that the LOP are
+configured on the client separately from the "promisor-remote"
+protocol and that the client accepts a LOP only when information about
+it from the protocol matches what has been already configured
+separately.
+
+What about LOP names?
+~~~~~~~~~~~~~~~~~~~~~
+
+In some contexts, for example if the clients sometimes fetch from each
+other, it can be a good idea for all the clients to use the same names
+for all the remotes they use, including LOPs.
+
+In other contexts, each client might want to be able to give the name
+it wants to each remote, including each LOP, it interacts with.
+
+So there should be different ways to configure how the client accepts
+or not the LOP name the server advertises.
+
+If a default or "safe" setting is used, then as such a setting should
+require that the LOP be configured separately, then the name would be
+configured separately and there is no risk that the server could
+dictate a name to a client.
+
+Could the main remote be bogged down by old or paranoid clients?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Yes, it could happen if there are too many clients that are either
+unwilling to trust the main remote or that just don't implement the
+"promisor-remote" protocol because they are too old or not fully
+compatible with the 'git' client.
+
+When serving such a client, the main remote has no other choice than
+to first fetch from its LOP, to then be able to provide to the client
+everything it requested. So the main remote, even if it has cleanup
+mechanisms (see section II.4 above), would be burdened at least
+temporarily with the large blobs it had to fetch from its LOP.
+
+Not behaving like this would be breaking backward compatibility, and
+could be seen as segregating clients. For example, it might be
+possible to implement a special mode that allows the server to just
+reject clients that don't implement the "promisor-remote" protocol or
+aren't willing to trust the main remote. This mode might be useful in
+a special context like a corporate environment. There is no plan to
+implement such a mode though, and this should be discussed separately
+later anyway.
+
+A better way to proceed is probably for the main remote to show a
+message telling clients that don't implement the protocol or are
+unwilling to accept the advertised LOP(s) that they would get faster
+clone and fetches by upgrading client software or properly setting
+them up to accept LOP(s).
+
+Waiting for clients to upgrade, monitoring these upgrades and limiting
+the use of LOPs to repos that are not very frequently accessed might
+be other good ways to make sure that some benefits are still reaped
+from LOPs. Over time, as more and more clients upgrade and benefit
+from LOPs, using them in more and more frequently accessed repos will
+become worth it.
+
+Corporate environments, where it might be easier to make sure that all
+the clients are up-to-date and properly configured, could hopefully
+benefit more and earlier from using LOPs.
+
+What about fetches?
+~~~~~~~~~~~~~~~~~~~
+
+There are different kinds of fetches. A regular fetch happens when
+some refs have been updated on the server and the client wants the ref
+updates and possibly the new objects added with them. A "backfill" or
+"lazy" fetch, on the contrary, happens when the client needs to use
+some objects it already knows about but doesn't have because they are
+on a promisor remote.
+
+Regular fetch
++++++++++++++
+
+In a regular fetch, the client will contact the main remote and a
+protocol negotiation will happen between them. It's a good thing that
+a protocol negotiation happens every time, as the configuration on the
+client or the main remote could have changed since the previous
+protocol negotiation. In this case, the new protocol negotiation
+should ensure that the new fetch will happen in a way that satisfies
+the new configuration of both the client and the server.
+
+In most cases though, the configurations on the client and the main
+remote will not have changed between 2 fetches or between the initial
+clone and a subsequent fetch. This means that the result of a new
+protocol negotiation will be the same as the previous result, so the
+new fetch will happen in the same way as the previous clone or fetch,
+using, or not using, the same LOP(s) as last time.
+
+"Backfill" or "lazy" fetch
+++++++++++++++++++++++++++
+
+When there is a backfill fetch, the client doesn't necessarily contact
+the main remote first. It will try to fetch from its promisor remotes
+in the order they appear in the config file, except that a remote
+configured using the `extensions.partialClone` config variable will be
+tried last. See
+link:partial-clone.html#using-many-promisor-remotes[the partial clone documentation].
+
+This is not new with this effort. In fact this is how multiple remotes
+have already been working for around 5 years.
+
+When using LOPs, having the main remote configured using
+`extensions.partialClone`, so it's tried last, makes sense, as missing
+objects should only be large blobs that are on LOPs.
+
+This means that a protocol negotiation will likely not happen as the
+missing objects will be fetched from the LOPs, and then there will be
+nothing left to fetch from the main remote.
+
+To secure that, it could be a good idea for LOPs to require a token
+from the client when it fetches from them. The client could get the
+token when performing a protocol negotiation with the main remote (see
+section II.6 above).
+
+V) Future improvements
+----------------------
+
+It is expected that at the beginning using LOPs will be mostly worth
+it either in a corporate context where the Git version that clients
+use can easily be controlled, or on repos that are infrequently
+accessed. (See the "Could the main remote be bogged down by old or
+paranoid clients?" section in the FAQ above.)
+
+Over time, as more and more clients upgrade to a version that
+implements the "promisor-remote" protocol v2 capability described
+above in section II.6), it will be worth it to use LOPs more widely.
+
+A lot of improvements may also help using LOPs more widely. Some of
+these improvements are part of the scope of this document like the
+following:
+
+  - Implementing a "remote-object-info" command in the
+    `git cat-file --batch` protocol and its variants to allow main
+    remotes to respond to requests about large blobs without fetching
+    them. (Eric Ju has started working on this based on previous work
+    by Calvin Wan.)
+
+  - Creating better cleanup and offload mechanisms for main remotes
+    and clients to prevent accumulation of large blobs.
+
+  - Developing more sophisticated protocol negotiation capabilities
+    between clients and servers for handling LOPs, for example adding
+    a filter-spec (e.g., blob:limit=<size>) or size limit for
+    filtering when cloning, or adding a token for LOP authentication.
+
+  - Improving security measures for LOP access, particularly around
+    token handling and authentication.
+
+  - Developing standardized ways to configure and manage multiple LOPs
+    across different environments. Especially in the case where
+    different LOPs serve the same content to clients in different
+    geographical locations, there is a need for replication or
+    synchronization between LOPs.
+
+Some improvements, including some that have been mentioned in the "0)
+Non Goals" section of this document, are out of the scope of this
+document:
+
+  - Implementing a new object representation for large blobs on the
+    client side.
+
+  - Developing pluggable ODBs or other object database backends that
+    could chunk large blobs, dedup the chunks and store them
+    efficiently.
+
+  - Optimizing data transfer between LOPs and clients/servers,
+    particularly for incompressible and non-deltifying content.
+
+  - Creating improved client side tools for managing large objects
+    more effectively, for example tools for migrating from Git LFS or
+    git-annex, or tools to find which objects could be offloaded and
+    how much disk space could be reclaimed by offloading them.
+
+Some improvements could be seen as part of the scope of this document,
+but might already have their own separate projects from the Git
+project, like:
+
+  - Improving existing remote helpers to access object storage or
+    developing new ones.
+
+  - Improving existing object storage solutions or developing new
+    ones.
+
+Even though all the above improvements may help, this document and the
+LOP effort should try to focus, at least first, on a relatively small
+number of improvements mostly those that are in its current scope.
+
+For example introducing pluggable ODBs and a new object database
+backend is likely a multi-year effort on its own that can happen
+separately in parallel. It has different technical requirements,
+touches other part of the Git code base and should have its own design
+document(s).
diff --git a/connect.c b/connect.c
index e6e25a0479..3280435331 100644
--- a/connect.c
+++ b/connect.c
@@ -22,6 +22,7 @@
 #include "protocol.h"
 #include "alias.h"
 #include "bundle-uri.h"
+#include "promisor-remote.h"
 
 static char *server_capabilities_v1;
 static struct strvec server_capabilities_v2 = STRVEC_INIT;
@@ -487,6 +488,7 @@ void check_stateless_delimiter(int stateless_rpc,
 static void send_capabilities(int fd_out, struct packet_reader *reader)
 {
 	const char *hash_name;
+	const char *promisor_remote_info;
 
 	if (server_supports_v2("agent"))
 		packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
@@ -500,6 +502,13 @@ static void send_capabilities(int fd_out, struct packet_reader *reader)
 	} else {
 		reader->hash_algo = &hash_algos[GIT_HASH_SHA1];
 	}
+	if (server_feature_v2("promisor-remote", &promisor_remote_info)) {
+		char *reply = promisor_remote_reply(promisor_remote_info);
+		if (reply) {
+			packet_write_fmt(fd_out, "promisor-remote=%s", reply);
+			free(reply);
+		}
+	}
 }
 
 int get_remote_bundle_uri(int fd_out, struct packet_reader *reader,
diff --git a/promisor-remote.c b/promisor-remote.c
index c714f4f007..6a0a61382f 100644
--- a/promisor-remote.c
+++ b/promisor-remote.c
@@ -11,6 +11,8 @@
 #include "strvec.h"
 #include "packfile.h"
 #include "environment.h"
+#include "url.h"
+#include "version.h"
 
 struct promisor_remote_config {
 	struct promisor_remote *promisors;
@@ -221,6 +223,18 @@ int repo_has_promisor_remote(struct repository *r)
 	return !!repo_promisor_remote_find(r, NULL);
 }
 
+int repo_has_accepted_promisor_remote(struct repository *r)
+{
+	struct promisor_remote *p;
+
+	promisor_remote_init(r);
+
+	for (p = r->promisor_remote_config->promisors; p; p = p->next)
+		if (p->accepted)
+			return 1;
+	return 0;
+}
+
 static int remove_fetched_oids(struct repository *repo,
 			       struct object_id **oids,
 			       int oid_nr, int to_free)
@@ -292,3 +306,231 @@ all_fetched:
 	if (to_free)
 		free(remaining_oids);
 }
+
+static int allow_unsanitized(char ch)
+{
+	if (ch == ',' || ch == ';' || ch == '%')
+		return 0;
+	return ch > 32 && ch < 127;
+}
+
+static void promisor_info_vecs(struct repository *repo,
+			       struct strvec *names,
+			       struct strvec *urls)
+{
+	struct promisor_remote *r;
+
+	promisor_remote_init(repo);
+
+	for (r = repo->promisor_remote_config->promisors; r; r = r->next) {
+		char *url;
+		char *url_key = xstrfmt("remote.%s.url", r->name);
+
+		strvec_push(names, r->name);
+		strvec_push(urls, git_config_get_string(url_key, &url) ? NULL : url);
+
+		free(url);
+		free(url_key);
+	}
+}
+
+char *promisor_remote_info(struct repository *repo)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int advertise_promisors = 0;
+	struct strvec names = STRVEC_INIT;
+	struct strvec urls = STRVEC_INIT;
+
+	git_config_get_bool("promisor.advertise", &advertise_promisors);
+
+	if (!advertise_promisors)
+		return NULL;
+
+	promisor_info_vecs(repo, &names, &urls);
+
+	if (!names.nr)
+		return NULL;
+
+	for (size_t i = 0; i < names.nr; i++) {
+		if (i)
+			strbuf_addch(&sb, ';');
+		strbuf_addstr(&sb, "name=");
+		strbuf_addstr_urlencode(&sb, names.v[i], allow_unsanitized);
+		if (urls.v[i]) {
+			strbuf_addstr(&sb, ",url=");
+			strbuf_addstr_urlencode(&sb, urls.v[i], allow_unsanitized);
+		}
+	}
+
+	strvec_clear(&names);
+	strvec_clear(&urls);
+
+	return strbuf_detach(&sb, NULL);
+}
+
+/*
+ * Find first index of 'nicks' where there is 'nick'. 'nick' is
+ * compared case insensitively to the strings in 'nicks'. If not found
+ * 'nicks->nr' is returned.
+ */
+static size_t remote_nick_find(struct strvec *nicks, const char *nick)
+{
+	for (size_t i = 0; i < nicks->nr; i++)
+		if (!strcasecmp(nicks->v[i], nick))
+			return i;
+	return nicks->nr;
+}
+
+enum accept_promisor {
+	ACCEPT_NONE = 0,
+	ACCEPT_KNOWN_URL,
+	ACCEPT_KNOWN_NAME,
+	ACCEPT_ALL
+};
+
+static int should_accept_remote(enum accept_promisor accept,
+				const char *remote_name, const char *remote_url,
+				struct strvec *names, struct strvec *urls)
+{
+	size_t i;
+
+	if (accept == ACCEPT_ALL)
+		return 1;
+
+	i = remote_nick_find(names, remote_name);
+
+	if (i >= names->nr)
+		/* We don't know about that remote */
+		return 0;
+
+	if (accept == ACCEPT_KNOWN_NAME)
+		return 1;
+
+	if (accept != ACCEPT_KNOWN_URL)
+		BUG("Unhandled 'enum accept_promisor' value '%d'", accept);
+
+	if (!strcmp(urls->v[i], remote_url))
+		return 1;
+
+	warning(_("known remote named '%s' but with url '%s' instead of '%s'"),
+		remote_name, urls->v[i], remote_url);
+
+	return 0;
+}
+
+static void filter_promisor_remote(struct repository *repo,
+				   struct strvec *accepted,
+				   const char *info)
+{
+	struct strbuf **remotes;
+	const char *accept_str;
+	enum accept_promisor accept = ACCEPT_NONE;
+	struct strvec names = STRVEC_INIT;
+	struct strvec urls = STRVEC_INIT;
+
+	if (!git_config_get_string_tmp("promisor.acceptfromserver", &accept_str)) {
+		if (!*accept_str || !strcasecmp("None", accept_str))
+			accept = ACCEPT_NONE;
+		else if (!strcasecmp("KnownUrl", accept_str))
+			accept = ACCEPT_KNOWN_URL;
+		else if (!strcasecmp("KnownName", accept_str))
+			accept = ACCEPT_KNOWN_NAME;
+		else if (!strcasecmp("All", accept_str))
+			accept = ACCEPT_ALL;
+		else
+			warning(_("unknown '%s' value for '%s' config option"),
+				accept_str, "promisor.acceptfromserver");
+	}
+
+	if (accept == ACCEPT_NONE)
+		return;
+
+	if (accept != ACCEPT_ALL)
+		promisor_info_vecs(repo, &names, &urls);
+
+	/* Parse remote info received */
+
+	remotes = strbuf_split_str(info, ';', 0);
+
+	for (size_t i = 0; remotes[i]; i++) {
+		struct strbuf **elems;
+		const char *remote_name = NULL;
+		const char *remote_url = NULL;
+		char *decoded_name = NULL;
+		char *decoded_url = NULL;
+
+		strbuf_strip_suffix(remotes[i], ";");
+		elems = strbuf_split(remotes[i], ',');
+
+		for (size_t j = 0; elems[j]; j++) {
+			int res;
+			strbuf_strip_suffix(elems[j], ",");
+			res = skip_prefix(elems[j]->buf, "name=", &remote_name) ||
+				skip_prefix(elems[j]->buf, "url=", &remote_url);
+			if (!res)
+				warning(_("unknown element '%s' from remote info"),
+					elems[j]->buf);
+		}
+
+		if (remote_name)
+			decoded_name = url_percent_decode(remote_name);
+		if (remote_url)
+			decoded_url = url_percent_decode(remote_url);
+
+		if (decoded_name && should_accept_remote(accept, decoded_name, decoded_url, &names, &urls))
+			strvec_push(accepted, decoded_name);
+
+		strbuf_list_free(elems);
+		free(decoded_name);
+		free(decoded_url);
+	}
+
+	strvec_clear(&names);
+	strvec_clear(&urls);
+	strbuf_list_free(remotes);
+}
+
+char *promisor_remote_reply(const char *info)
+{
+	struct strvec accepted = STRVEC_INIT;
+	struct strbuf reply = STRBUF_INIT;
+
+	filter_promisor_remote(the_repository, &accepted, info);
+
+	if (!accepted.nr)
+		return NULL;
+
+	for (size_t i = 0; i < accepted.nr; i++) {
+		if (i)
+			strbuf_addch(&reply, ';');
+		strbuf_addstr_urlencode(&reply, accepted.v[i], allow_unsanitized);
+	}
+
+	strvec_clear(&accepted);
+
+	return strbuf_detach(&reply, NULL);
+}
+
+void mark_promisor_remotes_as_accepted(struct repository *r, const char *remotes)
+{
+	struct strbuf **accepted_remotes = strbuf_split_str(remotes, ';', 0);
+
+	for (size_t i = 0; accepted_remotes[i]; i++) {
+		struct promisor_remote *p;
+		char *decoded_remote;
+
+		strbuf_strip_suffix(accepted_remotes[i], ";");
+		decoded_remote = url_percent_decode(accepted_remotes[i]->buf);
+
+		p = repo_promisor_remote_find(r, decoded_remote);
+		if (p)
+			p->accepted = 1;
+		else
+			warning(_("accepted promisor remote '%s' not found"),
+				decoded_remote);
+
+		free(decoded_remote);
+	}
+
+	strbuf_list_free(accepted_remotes);
+}
diff --git a/promisor-remote.h b/promisor-remote.h
index 88cb599c39..263d331a55 100644
--- a/promisor-remote.h
+++ b/promisor-remote.h
@@ -9,11 +9,13 @@ struct object_id;
  * Promisor remote linked list
  *
  * Information in its fields come from remote.XXX config entries or
- * from extensions.partialclone.
+ * from extensions.partialclone, except for 'accepted' which comes
+ * from protocol v2 capabilities exchange.
  */
 struct promisor_remote {
 	struct promisor_remote *next;
 	char *partial_clone_filter;
+	unsigned int accepted : 1;
 	const char name[FLEX_ARRAY];
 };
 
@@ -32,4 +34,37 @@ void promisor_remote_get_direct(struct repository *repo,
 				const struct object_id *oids,
 				int oid_nr);
 
+/*
+ * Prepare a "promisor-remote" advertisement by a server.
+ * Check the value of "promisor.advertise" and maybe the configured
+ * promisor remotes, if any, to prepare information to send in an
+ * advertisement.
+ * Return value is NULL if no promisor remote advertisement should be
+ * made. Otherwise it contains the names and urls of the advertised
+ * promisor remotes separated by ';'. See gitprotocol-v2(5).
+ */
+char *promisor_remote_info(struct repository *repo);
+
+/*
+ * Prepare a reply to a "promisor-remote" advertisement from a server.
+ * Check the value of "promisor.acceptfromserver" and maybe the
+ * configured promisor remotes, if any, to prepare the reply.
+ * Return value is NULL if no promisor remote from the server
+ * is accepted. Otherwise it contains the names of the accepted promisor
+ * remotes separated by ';'. See gitprotocol-v2(5).
+ */
+char *promisor_remote_reply(const char *info);
+
+/*
+ * Set the 'accepted' flag for some promisor remotes. Useful on the
+ * server side when some promisor remotes have been accepted by the
+ * client.
+ */
+void mark_promisor_remotes_as_accepted(struct repository *repo, const char *remotes);
+
+/*
+ * Has any promisor remote been accepted by the client?
+ */
+int repo_has_accepted_promisor_remote(struct repository *r);
+
 #endif /* PROMISOR_REMOTE_H */
diff --git a/serve.c b/serve.c
index f6dfe34a2b..e3ccf1505c 100644
--- a/serve.c
+++ b/serve.c
@@ -10,6 +10,7 @@
 #include "upload-pack.h"
 #include "bundle-uri.h"
 #include "trace2.h"
+#include "promisor-remote.h"
 
 static int advertise_sid = -1;
 static int advertise_object_info = -1;
@@ -29,6 +30,26 @@ static int agent_advertise(struct repository *r UNUSED,
 	return 1;
 }
 
+static int promisor_remote_advertise(struct repository *r,
+				     struct strbuf *value)
+{
+	if (value) {
+		char *info = promisor_remote_info(r);
+		if (!info)
+			return 0;
+		strbuf_addstr(value, info);
+		free(info);
+	}
+	return 1;
+}
+
+static void promisor_remote_receive(struct repository *r,
+				    const char *remotes)
+{
+	mark_promisor_remotes_as_accepted(r, remotes);
+}
+
+
 static int object_format_advertise(struct repository *r,
 				   struct strbuf *value)
 {
@@ -155,6 +176,11 @@ static struct protocol_capability capabilities[] = {
 		.advertise = bundle_uri_advertise,
 		.command = bundle_uri_command,
 	},
+	{
+		.name = "promisor-remote",
+		.advertise = promisor_remote_advertise,
+		.receive = promisor_remote_receive,
+	},
 };
 
 void protocol_v2_advertise_capabilities(struct repository *r)
diff --git a/t/meson.build b/t/meson.build
index daa26e41f5..a59da26be3 100644
--- a/t/meson.build
+++ b/t/meson.build
@@ -729,6 +729,7 @@ integration_tests = [
   't5703-upload-pack-ref-in-want.sh',
   't5704-protocol-violations.sh',
   't5705-session-id-in-capabilities.sh',
+  't5710-promisor-remote-capability.sh',
   't5730-protocol-v2-bundle-uri-file.sh',
   't5731-protocol-v2-bundle-uri-git.sh',
   't5732-protocol-v2-bundle-uri-http.sh',
diff --git a/t/t5710-promisor-remote-capability.sh b/t/t5710-promisor-remote-capability.sh
new file mode 100755
index 0000000000..d2cc69a17e
--- /dev/null
+++ b/t/t5710-promisor-remote-capability.sh
@@ -0,0 +1,312 @@
+#!/bin/sh
+
+test_description='handling of promisor remote advertisement'
+
+. ./test-lib.sh
+
+GIT_TEST_MULTI_PACK_INDEX=0
+GIT_TEST_MULTI_PACK_INDEX_WRITE_INCREMENTAL=0
+
+# Setup the repository with three commits, this way HEAD is always
+# available and we can hide commit 1 or 2.
+test_expect_success 'setup: create "template" repository' '
+	git init template &&
+	test_commit -C template 1 &&
+	test_commit -C template 2 &&
+	test_commit -C template 3 &&
+	test-tool genrandom foo 10240 >template/foo &&
+	git -C template add foo &&
+	git -C template commit -m foo
+'
+
+# A bare repo will act as a server repo with unpacked objects.
+test_expect_success 'setup: create bare "server" repository' '
+	git clone --bare --no-local template server &&
+	mv server/objects/pack/pack-* . &&
+	packfile=$(ls pack-*.pack) &&
+	git -C server unpack-objects --strict <"$packfile"
+'
+
+check_missing_objects () {
+	git -C "$1" rev-list --objects --all --missing=print > all.txt &&
+	perl -ne 'print if s/^[?]//' all.txt >missing.txt &&
+	test_line_count = "$2" missing.txt &&
+	if test "$2" -lt 2
+	then
+		test "$3" = "$(cat missing.txt)"
+	else
+		test -f "$3" &&
+		sort <"$3" >expected_sorted &&
+		sort <missing.txt >actual_sorted &&
+		test_cmp expected_sorted actual_sorted
+	fi
+}
+
+initialize_server () {
+	count="$1"
+	missing_oids="$2"
+
+	# Repack everything first
+	git -C server -c repack.writebitmaps=false repack -a -d &&
+
+	# Remove promisor file in case they exist, useful when reinitializing
+	rm -rf server/objects/pack/*.promisor &&
+
+	# Repack without the largest object and create a promisor pack on server
+	git -C server -c repack.writebitmaps=false repack -a -d \
+	    --filter=blob:limit=5k --filter-to="$(pwd)/pack" &&
+	promisor_file=$(ls server/objects/pack/*.pack | sed "s/\.pack/.promisor/") &&
+	>"$promisor_file" &&
+
+	# Check objects missing on the server
+	check_missing_objects server "$count" "$missing_oids"
+}
+
+copy_to_lop () {
+	oid_path="$(test_oid_to_path $1)" &&
+	path="server/objects/$oid_path" &&
+	path2="lop/objects/$oid_path" &&
+	mkdir -p $(dirname "$path2") &&
+	cp "$path" "$path2"
+}
+
+test_expect_success "setup for testing promisor remote advertisement" '
+	# Create another bare repo called "lop" (for Large Object Promisor)
+	git init --bare lop &&
+
+	# Copy the largest object from server to lop
+	obj="HEAD:foo" &&
+	oid="$(git -C server rev-parse $obj)" &&
+	copy_to_lop "$oid" &&
+
+	initialize_server 1 "$oid" &&
+
+	# Configure lop as promisor remote for server
+	git -C server remote add lop "file://$(pwd)/lop" &&
+	git -C server config remote.lop.promisor true &&
+
+	git -C lop config uploadpack.allowFilter true &&
+	git -C lop config uploadpack.allowAnySHA1InWant true &&
+	git -C server config uploadpack.allowFilter true &&
+	git -C server config uploadpack.allowAnySHA1InWant true
+'
+
+test_expect_success "clone with promisor.advertise set to 'true'" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
+		-c remote.lop.fetch="+refs/heads/*:refs/remotes/lop/*" \
+		-c remote.lop.url="file://$(pwd)/lop" \
+		-c promisor.acceptfromserver=All \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "clone with promisor.advertise set to 'false'" '
+	git -C server config promisor.advertise false &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
+		-c remote.lop.fetch="+refs/heads/*:refs/remotes/lop/*" \
+		-c remote.lop.url="file://$(pwd)/lop" \
+		-c promisor.acceptfromserver=All \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is not missing on the server
+	check_missing_objects server 0 "" &&
+
+	# Reinitialize server so that the largest object is missing again
+	initialize_server 1 "$oid"
+'
+
+test_expect_success "clone with promisor.acceptfromserver set to 'None'" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
+		-c remote.lop.fetch="+refs/heads/*:refs/remotes/lop/*" \
+		-c remote.lop.url="file://$(pwd)/lop" \
+		-c promisor.acceptfromserver=None \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is not missing on the server
+	check_missing_objects server 0 "" &&
+
+	# Reinitialize server so that the largest object is missing again
+	initialize_server 1 "$oid"
+'
+
+test_expect_success "init + fetch with promisor.advertise set to 'true'" '
+	git -C server config promisor.advertise true &&
+
+	test_when_finished "rm -rf client" &&
+	mkdir client &&
+	git -C client init &&
+	git -C client config remote.lop.promisor true &&
+	git -C client config remote.lop.fetch "+refs/heads/*:refs/remotes/lop/*" &&
+	git -C client config remote.lop.url "file://$(pwd)/lop" &&
+	git -C client config remote.server.url "file://$(pwd)/server" &&
+	git -C client config remote.server.fetch "+refs/heads/*:refs/remotes/server/*" &&
+	git -C client config promisor.acceptfromserver All &&
+	GIT_NO_LAZY_FETCH=0 git -C client fetch --filter="blob:limit=5k" server &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "clone with promisor.acceptfromserver set to 'KnownName'" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
+		-c remote.lop.fetch="+refs/heads/*:refs/remotes/lop/*" \
+		-c remote.lop.url="file://$(pwd)/lop" \
+		-c promisor.acceptfromserver=KnownName \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "clone with 'KnownName' and different remote names" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.serverTwo.promisor=true \
+		-c remote.serverTwo.fetch="+refs/heads/*:refs/remotes/lop/*" \
+		-c remote.serverTwo.url="file://$(pwd)/lop" \
+		-c promisor.acceptfromserver=KnownName \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is not missing on the server
+	check_missing_objects server 0 "" &&
+
+	# Reinitialize server so that the largest object is missing again
+	initialize_server 1 "$oid"
+'
+
+test_expect_success "clone with promisor.acceptfromserver set to 'KnownUrl'" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
+		-c remote.lop.fetch="+refs/heads/*:refs/remotes/lop/*" \
+		-c remote.lop.url="file://$(pwd)/lop" \
+		-c promisor.acceptfromserver=KnownUrl \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "clone with 'KnownUrl' and different remote urls" '
+	ln -s lop serverTwo &&
+
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
+		-c remote.lop.fetch="+refs/heads/*:refs/remotes/lop/*" \
+		-c remote.lop.url="file://$(pwd)/serverTwo" \
+		-c promisor.acceptfromserver=KnownUrl \
+		--no-local --filter="blob:limit=5k" server client &&
+	test_when_finished "rm -rf client" &&
+
+	# Check that the largest object is not missing on the server
+	check_missing_objects server 0 "" &&
+
+	# Reinitialize server so that the largest object is missing again
+	initialize_server 1 "$oid"
+'
+
+test_expect_success "clone with promisor.advertise set to 'true' but don't delete the client" '
+	git -C server config promisor.advertise true &&
+
+	# Clone from server to create a client
+	GIT_NO_LAZY_FETCH=0 git clone -c remote.lop.promisor=true \
+		-c remote.lop.fetch="+refs/heads/*:refs/remotes/lop/*" \
+		-c remote.lop.url="file://$(pwd)/lop" \
+		-c promisor.acceptfromserver=All \
+		--no-local --filter="blob:limit=5k" server client &&
+
+	# Check that the largest object is still missing on the server
+	check_missing_objects server 1 "$oid"
+'
+
+test_expect_success "setup for subsequent fetches" '
+	# Generate new commit with large blob
+	test-tool genrandom bar 10240 >template/bar &&
+	git -C template add bar &&
+	git -C template commit -m bar &&
+
+	# Fetch new commit with large blob
+	git -C server fetch origin &&
+	git -C server update-ref HEAD FETCH_HEAD &&
+	git -C server rev-parse HEAD >expected_head &&
+
+	# Repack everything twice and remove .promisor files before
+	# each repack. This makes sure everything gets repacked
+	# into a single packfile. The second repack is necessary
+	# because the first one fetches from lop and creates a new
+	# packfile and its associated .promisor file.
+
+	rm -f server/objects/pack/*.promisor &&
+	git -C server -c repack.writebitmaps=false repack -a -d &&
+	rm -f server/objects/pack/*.promisor &&
+	git -C server -c repack.writebitmaps=false repack -a -d &&
+
+	# Unpack everything
+	rm pack-* &&
+	mv server/objects/pack/pack-* . &&
+	packfile=$(ls pack-*.pack) &&
+	git -C server unpack-objects --strict <"$packfile" &&
+
+	# Copy new large object to lop
+	obj_bar="HEAD:bar" &&
+	oid_bar="$(git -C server rev-parse $obj_bar)" &&
+	copy_to_lop "$oid_bar" &&
+
+	# Reinitialize server so that the 2 largest objects are missing
+	printf "%s\n" "$oid" "$oid_bar" >expected_missing.txt &&
+	initialize_server 2 expected_missing.txt &&
+
+	# Create one more client
+	cp -r client client2
+'
+
+test_expect_success "subsequent fetch from a client when promisor.advertise is true" '
+	git -C server config promisor.advertise true &&
+
+	GIT_NO_LAZY_FETCH=0 git -C client pull origin &&
+
+	git -C client rev-parse HEAD >actual &&
+	test_cmp expected_head actual &&
+
+	cat client/bar >/dev/null &&
+
+	check_missing_objects server 2 expected_missing.txt
+'
+
+test_expect_success "subsequent fetch from a client when promisor.advertise is false" '
+	git -C server config promisor.advertise false &&
+
+	GIT_NO_LAZY_FETCH=0 git -C client2 pull origin &&
+
+	git -C client2 rev-parse HEAD >actual &&
+	test_cmp expected_head actual &&
+
+	cat client2/bar >/dev/null &&
+
+	check_missing_objects server 1 "$oid"
+'
+
+test_done
diff --git a/upload-pack.c b/upload-pack.c
index 728b2477fc..7498b45e2e 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -32,6 +32,7 @@
 #include "write-or-die.h"
 #include "json-writer.h"
 #include "strmap.h"
+#include "promisor-remote.h"
 
 /* Remember to update object flag allocation in object.h */
 #define THEY_HAVE	(1u << 11)
@@ -319,6 +320,8 @@ static void create_pack_file(struct upload_pack_data *pack_data,
 		strvec_push(&pack_objects.args, "--delta-base-offset");
 	if (pack_data->use_include_tag)
 		strvec_push(&pack_objects.args, "--include-tag");
+	if (repo_has_accepted_promisor_remote(the_repository))
+		strvec_push(&pack_objects.args, "--missing=allow-promisor");
 	if (pack_data->filter_options.choice) {
 		const char *spec =
 			expand_list_objects_filter_spec(&pack_data->filter_options);