The channel has been renamed as "RMC - The Cave" at least two or three years ago. Neil was already shortening the channel name into RMC in his videos, so to him this was a fairly easy decision to make. The main reason to do the change in the first place, is that the "Man Cave" part was originally a joke from his wife (a sign above the door to his hobby space) and not entirely fitting a channel that is now made (semi)-professionally in a space outside the house. He even has a computing museum nowadays so he wants to do all this without jokes that could be misinterpreted without context.
After the first wash cycle I turned the tune off. I mean, the guys putting the damn thing in place, your machine's legend, as well as the manual all tell you how.
Piece of advice: add -qv to your emerge command to let Portage show the things you need to know but stay quiet otherwise. Way less gets shown on the terminal window and on some systems it might slightly speed up the process.
.webm is but a container, so it cannot be considered (in)efficient on its own, only when considering the video and audio "formats" (no expert on the terminology) within (probably VP8 or 9 for video).
LineageOS depends on volunteers with knowledge, time, and access to the hardware in question. So sometimes they abandon certain phones (or never support at all).
That woman with her tongue out 😂