It's interesting you mention Zotero, I use Zotero all the time especially for university work. It has similar functionality in that it saves webpages. Is there any overlap with Singlefile? Or might the integrate?
That's excellent, I do use Singlefile as well but Zotero offer the database/citation functionality on top. Brilliant extension though, after ublock it's probably number 2 install for me.
Edit: I forgot to say that it's thanks to donations (a big thank you to Zotero) that I could have bought a Mac and paid the development license