Currently in the middle of finishing up the Alt-Tab PR for niri: https://github.com/YaLTeR/niri/pull/1704
Got most things working as I'd like, though still plenty of fixes and clean-ups left. Fully live window previews with block-out-from support and fading title labels.
There's some interesting design differences compared to other desktops: on niri I expect it's common to have multiple terminals open, so Alt-Tab must go by windows (not by apps) and must show previews big enough to pick the right one.
