Mozilla Firefox Manifest V3 and Manifest V2 Update

Given that MV2 is apparently here to stay in Firefox, I really wish Mozilla would implement Chrome's backported runtime per-tab permission model in it as well.

At this point, I find it very hard to justify installing extensions requesting the install-time "all data on all sites" permissions, but many popular extensions don't seem to be willing to upgrade to MV3 due to the restrictions this goes with on Chrome, and supporting two targets is probably too much work.