Thanks, MaxSem. I'm looking forward to a skin which only does skinning.
Specific hacks/overrides are indeed best discussed elsewhere, but the "last edited [by X] Y ago" is actually a good example. The change was tested on desktop and a decision was made to make it permanent. Instead, it ended up being applied on MobileFrontend only, morphed into something different and died there. https://www.mediawiki.org/wiki/Timestamp_position_modification
Nemo
P.s.: Speaking of ways to achieve concrete results in the immediate future, see the community discussion I just opened, "Proposal: restore normal editing permissions on all mobile sites". https://meta.wikimedia.org/w/index.php?title=Wikimedia_Forum&oldid=11276...