Profiles learn to share
A new share button sits on every profile and copies the link in one click. On phones it opens the system share sheet instead. If you back out, nothing happens.
Open a profile and a square 36-pixel share button now sits at the top right, beside Edit on GitHub on your own page or Follow on someone else's. Click it on a desktop and a toast says "Profile link copied." Tap it on a phone and the system share sheet slides up with "@octocat on /dev/null" and the profile link, ready for Messages or Mail. Guests see it too, no account needed.
Credit MrPunyapal, who taught the profile header one button and two habits. If your browser offers a share sheet, the button hands it the title and the profile link. If it doesn't, the link goes to your clipboard. The Follow control is pinned at 112 pixels, so Follow, Following and Unfollow stop shifting the row when you tap.
One catch. Backing out of the sheet stays silent only when the browser reports an abort. Any other share failure falls through to the clipboard, so you can get "Profile link copied" when the share you started never left the app. And if the clipboard itself is blocked, all you get is "Could not share profile."