Post 6.9 RC1 Branching Updates

[dream-encode]

Core Trac ticket: https://core.trac.wordpress.org/ticket/64235

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs. You can also manually ask me to refresh this list by adding the props-bot label.

Core Committers: Use this line as a base for the props when committing in SVN:

Props davidbaumwald, jorbin.

To understand the WordPress project's expectations around crediting contributors, please review the Contributor Attribution page in the Core Handbook.

[aaronjorbin]

version-support-mysql.json and .version-support-php.json both should also be updated. See https://core.trac.wordpress.org/changeset/60093

[github-actions]

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For more details about these limitations and more, check out the Limitations page in the WordPress Playground documentation.

Test this pull request with WordPress Playground.

[github-actions]

A commit was made that fixes the Trac ticket referenced in the description of this pull request.

SVN changeset: 61222
GitHub commit: 81e3dbe

This PR will be closed, but please confirm the accuracy of this and reopen if there is more work to be done.