There is a Versions in WordPress page in the Block Editor Handbook that explains which version of Gutenberg is bundled for each major version of WordPress.

This page is automatically generated based on the markdown files in the Gutenberg repository. This markdown file requires a manual PR to be submitted for each major update, as seen in this Gutenberg PR: WordPress/gutenberg#51984

However, it does not exist as a task list in the Releasing Major Versions page. How about adding something about this task in the Pre Beta 1 or Post Release section to ensure that future major updates do not forget this task?