Update `$_old_files` list for 7.1

[desrosj]

This ticket is for tracking the changes to the $_old_files list required for the 7.1 release.

Previously:

• #65273 (7.0)
• #64320 (6.9)
• #62150 (6.7)
• #61665 (6.6)
• #60648 (6.5)
• #59817 (6.4)
• #58994 (6.3)
• #57993 (6.2)
• #56934 (6.1)

[desrosj]

In 63031:

Upgrade/Install: Add removed icon files to $_old_files.

This adds the icon files removed during the 7.1 release to the $_old_files list.

Follow up to [62738], [62739].

Props courane01, wiildworks.
Fixes #65489. See #65813.

[desrosj]

In 63032:

Upgrade/Install: Correct $_old_files ordering for accuracy.

The wp-includes/js/dist/sync.js and wp-includes/js/dist/sync.min.js files were removed in 7.0.2 and added to the $_old_files list (see [62778]), but they are present again in trunk.

[62783] marked these files as reintroduced, but this comment should be moved above the file list added for 7.1.

Follow up to [62777], [62783], [63031].

See #65813, #65325.

[wildworks]

Quoting from Slack: ​https://wordpress.slack.com/archives/C0B4Q0RJVAT/p1786546686314159

The exception is the $_old_files one (which still needs to confirm that the sync.js file should actually be re-introduced in the release)

I've identified the cause. The reintroduction of sync.js was unintentional. Once https://github.com/WordPress/gutenberg/pull/81683 is synced to the core, both sync.js and sync.min.js should be removable.

wp-includes/js/dist/sync.js and sync.min.js were removed in 7.0.2, but came back in 7.1. This was not intentional: the sync package is only needed for real-time collaboration, which is not shipping in 7.1, and core has no server-side counterpart for it.

The two paths are currently commented out in $_old_files with a "Restored in WordPress 7.1." note. This PR restores them as active entries so that upgrading to 7.1 deletes the leftover files.

## Order of operations

These steps must be done in this order. Otherwise $_old_files will not match what is actually shipped, and grunt verify:build will fail because the files still exist in the build directory.

1. Merge ​https://github.com/WordPress/gutenberg/pull/81683. The sync package is then no longer exposed as a separate script on Gutenberg's wp/7.1 branch.
2. On the 7.1 branch of wordpress-develop, update the pinned Gutenberg hash to the latest commit of the wp/7.1 branch. sync.js and sync.min.js then disappear from core, and wp.sync is no longer exposed.
3. Finally, commit this PR.

Note that the stale src/wp-includes/js/dist/sync*.js files are not removed automatically by the build, since that directory is ignored by version control. They need to be deleted manually after step 2.

## Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Opus 5
Used for: Investigating when and why the files were reintroduced, and drafting this description. The change itself is a two-line edit that I reviewed and take responsibility for.

2. On the 7.1 branch of wordpress-develop, update the pinned Gutenberg hash to the latest commit of the wp/7.1 branch. sync.js and sync.min.js then disappear from core, and wp.sync is no longer exposed.
3. Finally, commit this PR.

Perhaps these two should be executed in a single commit.

This adds a temporary Grunt task to delete the remaining RTC-related files after building.

This is a temporary alternative approach to #13061/​https://github.com/WordPress/gutenberg/pull/81683.

Trac ticket: Core-65813

## Use of AI Tools

I don't have time to review this PR right now, but if ​https://github.com/WordPress/wordpress-develop/pull/13061 and ​https://github.com/WordPress/wordpress-develop/pull/13061 are not ready by the commit freeze, I think it's okay to proceed with this PR.

cc @ellatrix

I've updated the gutenberg.sha value to include the change from ​https://github.com/WordPress/gutenberg/pull/81683. After running the build script, the two files in question are now missing from the results.

Reviewed and tested ✅.

No defects found; the change looks safe to commit to the 7.1 branch.

Thank you all for your reviews! I'm glad we could address this issue before the commit freeze. I plan to update the GB Hash one more time before the commit freeze, as there are still a few PRs that need to be backported to 7.1.

Closing this in favor of #13061

[desrosj]

In 63316:

General: Bump the pinned hash for Gutenberg to 1984a80.

This updates the pinned commit hash of the Gutenberg repository from b9743a015526ac8fd79298fd4e96cf002cee333b to 1984a8058ff0c1465615ef88fe52e14cb207f6c0.

A full list of changes included in this commit can be found on GitHub: ​https://github.com/WordPress/gutenberg/compare/b9743a015526ac8fd79298fd4e96cf002cee333b..1984a8058ff0c1465615ef88fe52e14cb207f6c0.

The following commits are included:

• Theme: Avoid root-level relational selectors (​https://github.com/WordPress/gutenberg/pull/81673)
• Real-time collaboration: Bundle @wordpress/sync instead of exposing as wp.sync (​https://github.com/WordPress/gutenberg/pull/81683)

Props wildworks, desrosj, ellatrix, lancewillett, alecgeatches, annezazu.
Fixes #65813.

[desrosj]

Just confirmed that the two files were deleted from the build server as expected: ​https://build.trac.wordpress.org/changeset/62509.