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?