I really don’t see how supporting Manifest V3 is a problem. It’s still going to be used by many extension developers, and there’s no harm in its availability as long as you can still block WebRequest, which is currently the case. On the Mozilla taking Google’s money point, sure, that’s true, but it doesn’t seem to have affected too much of the browser, other than search defaults abd a few other things that can be very easily turned off or removed entirely. I wouldn’t say the chances are particularly high for Manifest V2 to be completely removed, personally.
~/src/
Simple, effective, doesn’t make my home folder any more of a mess than I already left it as.