I’ve seen a few quirks with using this with Firefox (including one site that had a bizarre redirect), but the method is leveraging their via proxy (https://web.hypothes.is/help/what-is-the-via-proxy/) so it should generally work regardless of having an add-on or not for almost any browser.

I’d seen some other odd behaviors in almost all mobile browsers in the past, but lately they all seem to have cleared up.