Running make linkcheck in Doc folder outputs thousands of broken and redirected status. It would be nice to clean this up so we can link-check Python in CI/CD for each commit, but right now it is too polluted.

Some of these occurrences could/should be fixed in the docs itself, others can benefit from Sphinx's linkcheck configs e.g. linkcheck_ignore and linkcheck_allow_redirect.

See linkcheck-log.txt for the full log as of commit f2b7ecb.

Fun stats obtained from the above file:

• Of its 8327 lines, where 7824 are related to BPO -> GH issues. Of 7824, 5744 lines are from whatsnew/changelog and only 20 are not from whatsnew/
• 241 lines are redirection of CPython CVS URL, fixing /tree/ to /blob/ in GitHub URL
• 28 lines are broken links, where one broken link is 'https://' from an example in whatsnet/changelog

The way I see, this steps divide in:

• Clean BPO to GH redirection messages
• Fix broken links
• Clean CPython CVS URL redirections
• Clean GH issues to GH PR redirections
• Fix the rest of the occurrences.

linkcheck_allow_redirect and linkcheck_ignore can be very handy in this case. linkcheck_allow_redirect makes 'ok' status a redirect that is being spotted by linkcheck, and we have linkcheck_ignore as the last resource.

Questions I have before implementing the solution:

• Documentation hosted by Read The Docs may have language enabled so example.com is redirected to example.com/en/latest. To handle occurrences, I could add them to linkcheck_allow_redirect or we can use sphinx-ext-intersphinx to map a keyword to the documentation URL (e.g 'rtd' for read-the-docs docs). The last option allows to map to proper language of the target URL linked, similar on how Weblate did)

• Is there any restrictions to fix broken/redirect links in old whatsnew/.rst?
• Is there any restrictions to fix broken/redirect links in old whatsnew/changelog.rst (i.e. Misc/NEWS)?
• Should I create a single Pull Request for all the fixes?

Linked PRs

• GH-103484: Docs: add linkcheck allowed redirects entries for most cases #103569
• [3.11] GH-103484: Docs: add linkcheck allowed redirects entries for most cases (GH-103569) #103602
• GH-103484: Fix broken links reported by linkcheck #103608
• [3.11] GH-103484: Fix broken links reported by linkcheck (GH-103608) #103683
• GH-103484: Fix redirected permanently URLs #104001
• [3.11] GH-103484: Fix redirected permanently URLs (GH-104001) #104088
• GH-103484: Tell linkcheck to ignore debian manpage redirects #123019
• [3.12] GH-103484: Tell linkcheck to ignore debian manpage redirects (GH-123019) #124136
• [3.13] GH-103484: Tell linkcheck to ignore debian manpage redirects (GH-123019) #124137
• GH-103484: Fix permanently redirects reported by linkcheck #124144
• [3.13] GH-103484: Fix permanently redirects reported by linkcheck (GH-124144) #124151
• [3.12] GH-103484: Fix permanently redirects reported by linkcheck (GH-124144) #124152
• GH-103484: Fix broken links reported by linkcheck #124169
• [3.13] GH-103484: Fix broken links reported by linkcheck (GH-124169) #124179
• [3.12] GH-103484: Fix broken links reported by linkcheck (GH-124169) #124180
• [3.12]: gh-103484: Relink _xxsubinterpretersmodule.c in whatsnew/3.12.rst #124183