My instant reaction was: "Wait?! They weren't immutable before?"
I'm glad they're doing this, and it's an unpleasant surprise that they didn't already work this way. I don't understand why they allow mutable releases.
We've had a few issues in the past where a file wasn't updated during the release process, requiring us to re-publish one small change. It's not optimal, but given the nature of our release process being long and complex it's a lot easier to fix the asset in three minutes rather than spend an entire day re-building and re-publishing an entire release, updating our docs, etc. just because of one line in one file that wasn't updated correctly.
I guess I'm just lucky, then, to have only dealt with release processes where it's no big deal to do a bump from 5.0.0 to 5.0.1 so I can address something like that. Some of them were long and complex, but they were scripted to the point where it was uniformly better to jump by a 0.0.1 than risk having two different releases with the exact same version # in the wild.
Any "given" name/ID (IE anything but the full hash) in a distributed VCS has to be mutable - without some single central arbiter of truth it's simply impossible.
I'm honestly a little surprised people seem to think they might be immutable - I guess maybe if people see "git" as "Actually Github"?
> Revocation in Sigstore. A recent post on this blog notes that signatures alone don’t tell you whether to trust an artifact; for that, you need a verification policy. This verification policy is a much more natural place to handle revocation than the identity layer; see Don’t Panic for an example. This allows us to avoid the scalability problems of global revocation lists (see CRLite for a discussion of these issues). The mantra here is revoke artifacts, not keys.
1. You could delete and re-create releases with the same name
2. You could delete and re-create tags with the same name, even if a release was pointing to that tag already
3. You could delete and re-create an asset that was uploaded to a release without doing any of the above.
By and large none of this is a problem on the surface, but you could imagine someone who gains access to a project's release credentials rebuilding a binary with a backdoor and replacing the existing, published version in the release with their new version after the fact.
An immutable release means that you could only inject that code during the release process by injecting the backdoor into the code itself, and since Github allows you to prevent code from entering a branch except through an approved PR and signed commits, it's possible to make that much more difficult or impractical.
"Before", it was trivial to move or delete tags and edit release assets. The only stable identifier available was the commit hash.
Immutable releases now enable permanently locking tags and releases to make supply chain attacks harder to affect users who are using release assets from before an attack occurred.
The previous behavior is still available by the way, I'm not sure what you meant by "before".
Anyone with the appropriate perms could replace binaries uploaded to the release at will. You could also change which commit a release's tag pointed to by deleting and re-creating the release (the link would end up the same since it just references the tag).
In Java with Maven these have a special suffix, "-SNAPSHOT". So "1.0.0-SNAPSHOT". Releases, like "1.0.0" are immutable once released. I always thought that was a pretty sane model.
Nobody thought about mutable releases being utterly bad _before_?
Baffles me...
As bad as hardware vendors selling products with different chips inside as the same model (hello Cisco -- at least in former times; hello HP, formerly selling at least three different, _incompatible_ laptop power supplies with the same label).
Mutability: surprise, surprise, I'm not what you expected! -- maybe one of IT's worst ideas.
Once in a while someone makes a mistake and it is helpful to just fix it.
I've done it myself, create a release, upload it, download to a different machine and discover it doesn't work there, so fix and retest. Only after all those steps do I hit send on the release announcement. This is a useful workflow (particularly the first time you release when you don't even know what you are doing).
So long as nobody abuses that mutable releases are a great thing. However a tiny minority of people are not trustworthy and so we are forced to take away a great things because of that minority.
Depending on the project, doing a re-release with an appended or updated version number might be a huge hassle. For a small, single-binary program run by an agile team it's pretty trivial to recall a release and publish a replacement, but for larger open-source projects with long, complex, release processes, paying customers, external docs, etc., spending an entire new day doing an entire new release to fix one typo in one word in one file in one artifact is less practical than just re-uploading the file and updating your SHA256SUMS.
> Nobody thought about mutable releases being utterly bad _before_? Baffles me...
Some of us been requesting it as a feature since 2016, just because it wasn't implemented until now doesn't mean even people inside GitHub hasn't thought about it.
It's funny they call it "adding a new layer of supply chain security", when I reported it in August 2015 I got this answer:
> Thanks for the submission. We have reviewed your report and determined that it does not present a security risk. Tags and releases are not directly associated. The author lookup for a given release is done when that release is created and not upon subsequent updates. I can see how that could lead to some confusing behavior. I passed your observations on to our developers to see if we would want to change that behavior in the future. But, given that it does not present a security risk, it is not eligible for reward under the Bug Bounty program.
> When you enable immutable releases, the following protections are enforced: • Git tags cannot be moved or deleted; • Release assets cannot be modified or deleted
On the face of it, this seems like a non-starter. If a particular immutable release represents a danger to the consumer (extreme example: the software contains a bug that could result in physical injury) one must have the ability to retract that release so that no further consumers of the software could be affected by it. It makes sense that a retraction of an immutable release should not be reversible in such a way that the release could be recreated with different contents. But retractions must be possible, for both ethical and legal reasons.
I would also argue that its not sufficient to simply apply a blanket "deny all" access control to dangerous releases (assuming such a mechanism exists), as this does not adequately convey the deprecating nature of the change (and as a result, could mistakenly be reversed in the future). Ideally the retraction itself would be immutable such that once retracted the release is inaccessible forever.
Now, it may be that all this is supported by the new feature; I haven't had the chance to test it yet. But nothing in the documentation makes this clear one way or another.
3. Removing the release completely (while keeping an audit log that this happened)
1 is for use-cases where availability trumps security. I'd argue this should never be the case but at the same time it is how our world ticks by and large. Hard to take this away from people.
2 is for security, forensics and heritage but at the cost of availability. Uninstallable could mean to only offer the artifacts in an archive.
3 must always be possible as a last resort for illegal content that slipped through all previous safeguard layers.
Your note on 3 brings up a good point: I'm sure that if there's a DMCA takedown notice or somesuch that GitHub will in fact delete your "immutable" release which "can't be deleted".
If I have anyone's attention there is something related I would like to see
Please add a small thing which users can look for on the public: repo/actions page
This small thing should let users know the action was run by github like is default and not run on a custom / private action runner
The private action runner feature makes sense but many projects tell users to look to the github action history to trust that tests A, B, C passed. If the github action ran on a private action runner then you really cannot trust that what is in e.g. run.yml actually ran
The attestation feature can be used to prove that an action was run by github and not by private / custom but users need to install the github cli to validate attestations and this is a heavy ask when I think an addition icon on repo/actions page or a diff icon color will do better
Just remember the only truly immutable release is one signed by a key the host does not have access to, or one where you pin a hash locally at the point of consumption.
Microsoft does not have strict third party code review policies internally, has been hit with supply chain attacks before, and will be hit again. Consider this a nice to have feature, but give it zero trust.
1. A release turns out to contain an exploitable bug
2. A release is published to fix the bug
3. Someone malicious with access deletes the release
4. Everyone downloading the "latest" version gets the exploitable version until the developers notice and re-publish again
I think about tools used in CI systems that are often re-downloaded in each run, like `helm` or `kubectl` or `crane` for example; if they're pinning a previous version they stay exploitable, and if they're downloading the 'latest' from Github then this switcheroo keeps them exploitable. Given that a lot of emergency security releases come with disclosure ("this is being released to resolve CVE-2025-12345") another 12 hours of exploitability can be critical.
Thanks, interesting scenario, but if you have access to releases like that how is this easier vs just publishing a release with an exploit and getting the same X hours before you're discovered?
Deletion creates a hole. The hole can be filled by something else. This is a form of mutation.
What you probably want instead is one-way revocation. You place a permanent marker that says "do not use this release because it is {broken, malicious, ...}".
An "immutable hole" just sounds like a "revocation marker" without an accompanying message, so I don't think we're really asking for different things, here. Nevertheless, ordinary tag deletion -- what git natively supports -- can't be supported directly.
The difference is the unavailability of content. For example, you attach the wrong binary and want to avoid confusion/mistaken downloads either manual or via tools that don't support your markers, in the most direct way - by deleting the binary from release.
But you can't fix it if you opted into the security benefits of no hidden mutation
Strange they haven't identified negative security implications: if the owner notices the hack he can delete the malicious release before the central authority, so this would limit the blast radius (think there was a recent such issue with npm where there was a delay between discovery (by the author) and removal)
Which means the tainted release doesn't matter anymore to those consumers worried about the immutable release attestation anyways. If others are worried about that, they should probably consume only attested immutable releases as well.
I'd still bet the larger portion was it was just a particularly easy path to preventing downgrade attacks or the like though. Could always be more to it as well I'm not thinking of, just feels likely.
This seems too strong to me, especially the prohibition on deletion. Why couldn't they have instead just showed a record of modifications to releases, and/or embedded a hash of the contents in the URL to them?
As I'm working on a signing scheme for release authentication, this is a welcome news.
To alleviate the issue of mutable releases I had set up a mirror of releases checksums to be able to detect releases alterations. This is not needed anymore for immutable releases.
And automatically publishing checking of releases artifacts is also a good recent change by GH: in that project mentioned above I have developed a cli downloader checking the checksums of the downloaded file [1], but to be useful, it required the project to publish checksums, and the project to be mirrored. Now both of these requirements are dropped and the tool is readily useful for all GitHub immutable releases.
Would've made more sense to add a grey "Edited" to edited releases. Releases are not actually immutable, GitHub could change them. I don't know why you need to use sciency words to say "editing disabled".
They are immutable! The releases are signed with an attestation from a trusted third party that Github can't forge! Also these attestations are public and anyone can verify that the signing third party isn't misbehaving.
> Release attestations let you verify that an artifact is authentic and unchanged, even outside GitHub. Attestations use the Sigstore bundle format, so you can easily verify releases and assets using the GitHub CLI or integrate with any Sigstore-compatible tooling to automate policy enforcement in your CI/CD pipelines. For instructions on how to verify the integrity of a release, see our docs on verifying the integrity of a release.
They are using Sigstore, which is pretty standard in this space.
I love the idea but I fear the implementation. I don’t use GitHub actions for builds and upload ancillary artifacts to releases. I guess I know what will be my distraction today.
Uh, does this apply to the autogenerated source code artifacts? Those are famously not stable because they are generated on-demand with `git archive`. The value of this feature is really undermined if they don't also provide a source code download with a stable hash.
I struggle to get excited about this sort of thing when the most essential functions of GitHub are falling apart. Reviewing PRs has somehow gotten even worse since the original react update.
I think the only thing that would fix this issue is for them to lose 20%+ of their customers to a competitor. Something very simple that can vacuum up the GHES migration archive and proceed as if it were 2018 again.
I'd be willing to completely sacrifice actions, project boards, copilot, et. al. if it meant I could have ultra fast views into code, issues and pulls. I really see no reason the PR view cannot be pre-rendered on the server when the branch is pushed each time. This should be an instantaneous response at review time. I don't care if it's 5 megabytes of diff - If my browser can handle the react slop, it can certainly handle a big chunk of static DOM.
My instant reaction was: "Wait?! They weren't immutable before?"
I'm glad they're doing this, and it's an unpleasant surprise that they didn't already work this way. I don't understand why they allow mutable releases.
We've had a few issues in the past where a file wasn't updated during the release process, requiring us to re-publish one small change. It's not optimal, but given the nature of our release process being long and complex it's a lot easier to fix the asset in three minutes rather than spend an entire day re-building and re-publishing an entire release, updating our docs, etc. just because of one line in one file that wasn't updated correctly.
I guess I'm just lucky, then, to have only dealt with release processes where it's no big deal to do a bump from 5.0.0 to 5.0.1 so I can address something like that. Some of them were long and complex, but they were scripted to the point where it was uniformly better to jump by a 0.0.1 than risk having two different releases with the exact same version # in the wild.
Yeah, depending on the size of the project you could end up having thousands of users downloading and installing 5.0.0 and then complaining.
Git tags aren’t even really immutable, they’re treated as such but they’re not.
Any "given" name/ID (IE anything but the full hash) in a distributed VCS has to be mutable - without some single central arbiter of truth it's simply impossible.
I'm honestly a little surprised people seem to think they might be immutable - I guess maybe if people see "git" as "Actually Github"?
GitHub docs > Signing tags: https://docs.github.com/en/authentication/managing-commit-si... :
> You can sign tags locally using GPG, SSH, or S/MIME
Git book > 7.4 Git Tools - Signing Your Work: https://git-scm.com/book/ms/v2/Git-Tools-Signing-Your-Work :But you can still delete and recreate/sign the same tag again.
But GitHub has the option to prevent this. Just like branches.
Sigstore.dev supports revocation:
"Don’t Panic: A Playbook for Handling Account Compromise with Sigstore" (2022) https://blog.sigstore.dev/dont-panic-a-playbook-for-handling...
"Why you can’t use Sigstore without Sigstore" (2023) https://blog.sigstore.dev/why-you-cant-use-sigstore-without-... :
> Revocation in Sigstore. A recent post on this blog notes that signatures alone don’t tell you whether to trust an artifact; for that, you need a verification policy. This verification policy is a much more natural place to handle revocation than the identity layer; see Don’t Panic for an example. This allows us to avoid the scalability problems of global revocation lists (see CRLite for a discussion of these issues). The mantra here is revoke artifacts, not keys.
Artifact Attestation > Verifying an artifact attestation for binaries: https://docs.github.com/en/actions/how-tos/secure-your-work/... :
If it is not possible to retract/revoke releases then, there again, the installer MUST verify against a signed list of revoked releasesYeah, how did it work before that it was not immutable?!
> With immutable releases, assets and tags are protected from tampering after publication
I really, really wonder how it worked before. Can anyone explain?
1. You could delete and re-create releases with the same name
2. You could delete and re-create tags with the same name, even if a release was pointing to that tag already
3. You could delete and re-create an asset that was uploaded to a release without doing any of the above.
By and large none of this is a problem on the surface, but you could imagine someone who gains access to a project's release credentials rebuilding a binary with a backdoor and replacing the existing, published version in the release with their new version after the fact.
An immutable release means that you could only inject that code during the release process by injecting the backdoor into the code itself, and since Github allows you to prevent code from entering a branch except through an approved PR and signed commits, it's possible to make that much more difficult or impractical.
Thank you!
"Before", it was trivial to move or delete tags and edit release assets. The only stable identifier available was the commit hash.
Immutable releases now enable permanently locking tags and releases to make supply chain attacks harder to affect users who are using release assets from before an attack occurred.
The previous behavior is still available by the way, I'm not sure what you meant by "before".
> The previous behavior is still available by the way, I'm not sure what you meant by "before".
I know, I was just wondering how it worked that needed this improvement.
Anyone with the appropriate perms could replace binaries uploaded to the release at will. You could also change which commit a release's tag pointed to by deleting and re-creating the release (the link would end up the same since it just references the tag).
Mutable releases are used for continuous/nightly builds.
In Java with Maven these have a special suffix, "-SNAPSHOT". So "1.0.0-SNAPSHOT". Releases, like "1.0.0" are immutable once released. I always thought that was a pretty sane model.
+1
Nobody thought about mutable releases being utterly bad _before_? Baffles me...
As bad as hardware vendors selling products with different chips inside as the same model (hello Cisco -- at least in former times; hello HP, formerly selling at least three different, _incompatible_ laptop power supplies with the same label).
Mutability: surprise, surprise, I'm not what you expected! -- maybe one of IT's worst ideas.
Once in a while someone makes a mistake and it is helpful to just fix it.
I've done it myself, create a release, upload it, download to a different machine and discover it doesn't work there, so fix and retest. Only after all those steps do I hit send on the release announcement. This is a useful workflow (particularly the first time you release when you don't even know what you are doing).
So long as nobody abuses that mutable releases are a great thing. However a tiny minority of people are not trustworthy and so we are forced to take away a great things because of that minority.
That is what ‘-1’ and the like are for.
Depending on the project, doing a re-release with an appended or updated version number might be a huge hassle. For a small, single-binary program run by an agile team it's pretty trivial to recall a release and publish a replacement, but for larger open-source projects with long, complex, release processes, paying customers, external docs, etc., spending an entire new day doing an entire new release to fix one typo in one word in one file in one artifact is less practical than just re-uploading the file and updating your SHA256SUMS.
In that case, it seems like immutable releases aren't what that project wants. You don't HAVE to enable immutable releases.
The ability to change a release is fundamentally incompatible with immutable releases, by definition. You can have one or the other, not both.
immutable releases are not what anyone wants. A few bad actors forced them on us.
> Nobody thought about mutable releases being utterly bad _before_? Baffles me...
Some of us been requesting it as a feature since 2016, just because it wasn't implemented until now doesn't mean even people inside GitHub hasn't thought about it.
It's funny they call it "adding a new layer of supply chain security", when I reported it in August 2015 I got this answer:
> Thanks for the submission. We have reviewed your report and determined that it does not present a security risk. Tags and releases are not directly associated. The author lookup for a given release is done when that release is created and not upon subsequent updates. I can see how that could lead to some confusing behavior. I passed your observations on to our developers to see if we would want to change that behavior in the future. But, given that it does not present a security risk, it is not eligible for reward under the Bug Bounty program.
> When you enable immutable releases, the following protections are enforced: • Git tags cannot be moved or deleted; • Release assets cannot be modified or deleted
On the face of it, this seems like a non-starter. If a particular immutable release represents a danger to the consumer (extreme example: the software contains a bug that could result in physical injury) one must have the ability to retract that release so that no further consumers of the software could be affected by it. It makes sense that a retraction of an immutable release should not be reversible in such a way that the release could be recreated with different contents. But retractions must be possible, for both ethical and legal reasons.
I would also argue that its not sufficient to simply apply a blanket "deny all" access control to dangerous releases (assuming such a mechanism exists), as this does not adequately convey the deprecating nature of the change (and as a result, could mistakenly be reversed in the future). Ideally the retraction itself would be immutable such that once retracted the release is inaccessible forever.
Now, it may be that all this is supported by the new feature; I haven't had the chance to test it yet. But nothing in the documentation makes this clear one way or another.
I think there are compelling reasons to support:
1. Unremovable
2. Uninstallable while keeping the data available
3. Removing the release completely (while keeping an audit log that this happened)
1 is for use-cases where availability trumps security. I'd argue this should never be the case but at the same time it is how our world ticks by and large. Hard to take this away from people.
2 is for security, forensics and heritage but at the cost of availability. Uninstallable could mean to only offer the artifacts in an archive.
3 must always be possible as a last resort for illegal content that slipped through all previous safeguard layers.
Your note on 3 brings up a good point: I'm sure that if there's a DMCA takedown notice or somesuch that GitHub will in fact delete your "immutable" release which "can't be deleted".
I am glad for this feature
If I have anyone's attention there is something related I would like to see
Please add a small thing which users can look for on the public: repo/actions page
This small thing should let users know the action was run by github like is default and not run on a custom / private action runner
The private action runner feature makes sense but many projects tell users to look to the github action history to trust that tests A, B, C passed. If the github action ran on a private action runner then you really cannot trust that what is in e.g. run.yml actually ran
The attestation feature can be used to prove that an action was run by github and not by private / custom but users need to install the github cli to validate attestations and this is a heavy ask when I think an addition icon on repo/actions page or a diff icon color will do better
I am seeing some docs now that suggest
> runs-on: [self-hosted, ...]
Must be added to run.yml to use custom / private action runners
I did not find these docs last time I looked and so my feature request may be already fulfilled
If anyone wants to chime in to say that `runs-on` can be relied on or not I would be grateful
Just remember the only truly immutable release is one signed by a key the host does not have access to, or one where you pin a hash locally at the point of consumption.
Microsoft does not have strict third party code review policies internally, has been hit with supply chain attacks before, and will be hit again. Consider this a nice to have feature, but give it zero trust.
Why is deletion not allowed, which supply chain attacks work by deleting a release, not changing it to a malicious one?
1. A release turns out to contain an exploitable bug
2. A release is published to fix the bug
3. Someone malicious with access deletes the release
4. Everyone downloading the "latest" version gets the exploitable version until the developers notice and re-publish again
I think about tools used in CI systems that are often re-downloaded in each run, like `helm` or `kubectl` or `crane` for example; if they're pinning a previous version they stay exploitable, and if they're downloading the 'latest' from Github then this switcheroo keeps them exploitable. Given that a lot of emergency security releases come with disclosure ("this is being released to resolve CVE-2025-12345") another 12 hours of exploitability can be critical.
Thanks, interesting scenario, but if you have access to releases like that how is this easier vs just publishing a release with an exploit and getting the same X hours before you're discovered?
Deletion creates a hole. The hole can be filled by something else. This is a form of mutation.
What you probably want instead is one-way revocation. You place a permanent marker that says "do not use this release because it is {broken, malicious, ...}".
No, you can make the whole immutable, that is if a tag in an immutable repo was used and deleted, it can't be used again
An "immutable hole" just sounds like a "revocation marker" without an accompanying message, so I don't think we're really asking for different things, here. Nevertheless, ordinary tag deletion -- what git natively supports -- can't be supported directly.
The difference is the unavailability of content. For example, you attach the wrong binary and want to avoid confusion/mistaken downloads either manual or via tools that don't support your markers, in the most direct way - by deleting the binary from release. But you can't fix it if you opted into the security benefits of no hidden mutation
I think the reason here is to prevent deletion that cause upstream disruptions.
See the reasoning in the PEP 763 (not adopted )
https://peps.python.org/pep-0763/
Strange they haven't identified negative security implications: if the owner notices the hack he can delete the malicious release before the central authority, so this would limit the blast radius (think there was a recent such issue with npm where there was a delay between discovery (by the author) and removal)
Otherwise yes, leftpad/coverup risk is a thing
I'd guess one MO is to delete a malicious package/url shortly after releasing it to prevent researchers from getting to it.
So they wouldn't make a release immutable?
Which means the tainted release doesn't matter anymore to those consumers worried about the immutable release attestation anyways. If others are worried about that, they should probably consume only attested immutable releases as well.
I'd still bet the larger portion was it was just a particularly easy path to preventing downgrade attacks or the like though. Could always be more to it as well I'm not thinking of, just feels likely.
I assume they're doing the trivial workaround to prevent renaming by way of delete and recreate?
Then you'd ban the recreation part?
This seems too strong to me, especially the prohibition on deletion. Why couldn't they have instead just showed a record of modifications to releases, and/or embedded a hash of the contents in the URL to them?
As I'm working on a signing scheme for release authentication, this is a welcome news.
To alleviate the issue of mutable releases I had set up a mirror of releases checksums to be able to detect releases alterations. This is not needed anymore for immutable releases.
And automatically publishing checking of releases artifacts is also a good recent change by GH: in that project mentioned above I have developed a cli downloader checking the checksums of the downloaded file [1], but to be useful, it required the project to publish checksums, and the project to be mirrored. Now both of these requirements are dropped and the tool is readily useful for all GitHub immutable releases.
1: https://github.com/asfaload/asfald/
For a user is there an easy way to see in the UI whether a given Github repo's releases are immutable?
> If a release is immutable, you will see " Immutable" below the title on the release page.
https://docs.github.com/en/code-security/supply-chain-securi...
Wonderful, thank you!
Would've made more sense to add a grey "Edited" to edited releases. Releases are not actually immutable, GitHub could change them. I don't know why you need to use sciency words to say "editing disabled".
They are immutable! The releases are signed with an attestation from a trusted third party that Github can't forge! Also these attestations are public and anyone can verify that the signing third party isn't misbehaving.
> Release attestations let you verify that an artifact is authentic and unchanged, even outside GitHub. Attestations use the Sigstore bundle format, so you can easily verify releases and assets using the GitHub CLI or integrate with any Sigstore-compatible tooling to automate policy enforcement in your CI/CD pipelines. For instructions on how to verify the integrity of a release, see our docs on verifying the integrity of a release.
They are using Sigstore, which is pretty standard in this space.
I love the idea but I fear the implementation. I don’t use GitHub actions for builds and upload ancillary artifacts to releases. I guess I know what will be my distraction today.
And yet I received an update from
to So someone must've moved the tag, even though that release is supposed to be immutable. https://github.com/github/codeql-action/releasesThat release isn't immutable
Uh, does this apply to the autogenerated source code artifacts? Those are famously not stable because they are generated on-demand with `git archive`. The value of this feature is really undermined if they don't also provide a source code download with a stable hash.
Well I guess they're doing something at least. I kind of thought Github had moved to maintenance mode. Maybe we'll get stacked PRs one day?
I struggle to get excited about this sort of thing when the most essential functions of GitHub are falling apart. Reviewing PRs has somehow gotten even worse since the original react update.
I think the only thing that would fix this issue is for them to lose 20%+ of their customers to a competitor. Something very simple that can vacuum up the GHES migration archive and proceed as if it were 2018 again.
I'd be willing to completely sacrifice actions, project boards, copilot, et. al. if it meant I could have ultra fast views into code, issues and pulls. I really see no reason the PR view cannot be pre-rendered on the server when the branch is pushed each time. This should be an instantaneous response at review time. I don't care if it's 5 megabytes of diff - If my browser can handle the react slop, it can certainly handle a big chunk of static DOM.
If it happens, it would likely be fully integrated versioning in some LLM product.