Earlier quoted context omitted.
This is the main reason I stay away from Vivaldi; using Firefox is, for all of Mozilla's borderline comical mismanagement, a protest vote against Blink (and previously, Chromium).
This has been a lost cause for the past decade or so. Web developers don't target Firefox anymore because a 5% share isn't enough to matter. Both projects (Chromium and Firefox) are open, so it's like Linux vs FreeBSD, but at least FreeBSD has a clear licensing advantage.
No defeatism though please, some of us will advocate till the end (pen & paper)