Further to @Benoit Grégoire's article, here are some MR's for backports i'm currently or recently been involved in.

Combined backport of the various fixes trying to resolve regressions from sections refactoring

• This is attempting to correct regressions caused by !8658 , !9802 , !9703 (which i think was reverted), and maybe others.
• Release blocker: item8949-Admin-theme-is-used-for-whole-site-theme-switch-module-doesn't-work and others arising.

map fixes and updates for upgrading cartograf to tiki 30+

• This was intended to go in Tiki 30.0 but reality, and the size of the challenge, means it won't make it but would be a good addition to 30.1 and the funding for it depends on that.
• It finally upgrades the rest of the mapping features to be able to run on a supported version of OpenLayers, the previous version OL2 having been removed in !5534 in 2024, without replacement code being added.
• These features were developed for Cartograf and are still in use on cartograf.learnquebec.ca, run by LEARN who are funding the upgrade. The development server is available here cartografdev.learnquebec.ca and is running on the !10415 branch.

Full list (too many to analyse now) here

• gitlab.com/tikiwiki/tiki/-/merge_requests/ jonnybradley Backported

I suppose one fairly easy category to define is for [FIX]es in master to be backported to latest stable, where relevant (i.e. the thing being fixed is in the XX.x branch). This is especially so before the release of XX.0, as we are, for example, trying to do now.