It's a dependency of a lot of things, including git, lxc, GNU autotools. Check the Required By on the Archlinux repo.

With recent drivers and recent enough DEs it is usable to a certain extent. There are some known issues documented in the release notes of each version. Here's for 535. TL; DR the major blockers are: (1) Variable Refresh Rate doesn't work for some cards; (2) GAMMA_LUT is not implemented (no night light) and (3) Nested X11 clients have synchronisation issues that might result in some flickering or dupicate frames, it's more noticeable on things that refresh slowly, although much better recently. Also (4) NvFBC capture doesn't work with nested X11 clients which might or might not be important for some people.

I'm using it with Plasma; it's OK, no major concerns but my setup is pretty basic.

Apple will add support for JXL natively on the new macOS/iOS. Adobe suite added support recently. And yet Chrome decided to kill JXL before there was even a chance of gaining enough traction. This effectively kills any chance of widespread adoption of the format, which is a shame because it looks like it has a decent featureset. I really like that you can reencode the same picture with effectively no quality loss.

It's never been about the API. Third party apps are undercutting Reddit's as revenue. They could never ban the apps outright so they set an obscene cost for API calls to indirectly kill them. They have probably factored in the potential loss of users already and it probably ain't much.

Unlikely. When users left Digg for Reddit the internet was smaller and the users more technically minded. And even then it was essentially just creating a new account. You need an one stop solution for users to migrate and federation by definition isn't that. As a result discovery (and growth) is still hard even for Mastodon that's been around for a while and it's a relatively mature platform.