CIRCLE WITH A DOT

@jrredho @scholar_farmer OK, I didn't know that, thanks for the clarification!

@scholar_farmer I *think* Zotero can work only locally... But not 100% sure (I do have it synced between two computers)

@scholar_farmer I mostly use Okular for annotations and such. I'm not sure, but it's maybe Linux only.
An alternative, if this is to read and annotate academic papers, is Zotero. It's mostly to keep a database of your papers, but it also has a pretty decent annotation tool for PDFs.