Mozilla mismanages Firefox for several years, and dropped Thunderbird. I can't use Firefox even for dev work anymore because of too many regression bugs and new

Mozilla mismanages Firefox for several years, and dropped Thunderbird. I can't use Firefox even for dev work anymore because of too many regression bugs and newly introduced UI annoyance and removal of classic addon-API, etc. The Rust/Servo movement is good, but Firefox needs badly a reboot/lightweight fork. I suggest to have a look at Iron browser (open source Chromium with phone-home stuff patched out) or Chromium build in general (with curated settings or stuff patched out yourself). And Vivaldi (reminds one to older Opera UI) is quite good, though closed source.