[osrec]

I had a quick look at Zotero's github but couldn't quite work out how they render their desktop UI - is this an electron-style app or a browser extension of some sort?

[gmac]

It's XUL. It used to be a Firefox extension, before Firefox changed how those work.

[OJFord]

I haven't used it in a couple of years, but then it seemed to be using Qt/GTK/something.

I believe there is a browser extension too, but the main program is (was) a non-electron stand-alone deal.