Keeping things working is not solely the task of mozilla devs, extension developers have to do their part too.
Sometimes it's easy easy as toggling off some experimental feature or installing a beta build of that extension.
At other times you'll have to report a bug yourself.
And sometimes extensions just die because they're unmaintained. It happens eventually.
That's nothing unique to developer edition. You're just more likely to see something that'll trickle down to release builds soon anyway.
Personally I've managed to live with some annoyances on nightly for a few weeks until they got fixed.
e: cmd+shift+e assumes a Mac. Not sure what other systems use.
Losing tree style tabs in 42 has made me nervous, it was the primary reason I love firefox. Without that most of the why in using firefox goes away for me.
https://www.palemoon.org/technical.shtml#features
As I understand, the author's opinion is that Adobe Reader is more secure than pdf.js. I'm not sure I would trust them with maintaining a secure browser in light of that.
Their monetization model is also questionable (I understand it injects ads / referral links).
Any source for that? A quick search didn't turn up anything and seeing as Pale Moon is now on my shortlist of Firefox alternatives I'd be interested.
That is overall fine but I like to keep my browsers portable across all of my primary operating systems.
Still, it is just a forked Firefox so it uses the same extensions etc for now, maybe using FF on Mac and PM on the other platforms would be possible?