Followed the 1st link in post, used GitHub sign-up button, allowed pop-up, signed in to GH, authorized app, ended up on white page with message about missing session status or something (sorry, I didn't capture verbatim message).
Went back to 1st page and tried again. No GH login prompt, white page with coloured progress bar at top, ended up back on initial page with message "Unable to establish a connection with the popup. It may have been blocked by the browser".
Firefox on Android.
(Btw, perhaps it's on purpose, but I can't select and copy text on that page.)
Went back to 1st page and tried again. No GH login prompt, white page with coloured progress bar at top, ended up back on initial page with message "Unable to establish a connection with the popup. It may have been blocked by the browser".
Firefox on Android. (Btw, perhaps it's on purpose, but I can't select and copy text on that page.)