"Like I said the only option for Firefox, apparently, is downloading the H.265 video, transcoding it to H.264 via Ffmpeg, then viewing it in Firefox."
I'm running Linux debian 4.19.0-22-amd64 #1 SMP Debian 4.19.260-1 (2022-09-29) x86_64 GNU/Linux with Firefox 102.5.Oesr and I can play this HEVC H.265 Youtube test video, https://www.youtube.com/watch?v=Fa2bL--exAM
