> there was a big uproar (rightly so) when Mozilla cut a lot of stuff that wasn't directly related to Firefox, such as MDN web docs or the experimental Servo browser engine.

MDN is a documentation site for the technologies supported by Firefox. Servo is a browser engine that's been used as a development target for efforts to rewrite major components of Firefox. These are both directly related to Firefox, as were other things that were cut.

From my vantage I don't recall the outrage whether things being cut were / weren't related to Firefox, but rather that major cuts were being made at the bottom (to features / programmes / staff) while Mozilla management were exorbitantly remunerated and receiving large bonuses/raises at the same time. Despite the severe decline in Firefox seen under their tenure.