Upstream: https://we.phorge.it/T15986
This was introduced in https://we.phorge.it/rP568b0e06e7d54618c2afade1cf409912bf90add9.
Personally speaking, this prefix only makes spotting the page title in a browser tab harder when having numerous tabs opened.
Plus my workflows don't rely on web notifications.
Plus every single opened Phabricator page shows that number in the top bar anyway. Is it so important to see it also when having another browser tab opened? I understand that "sense of urgency" which other social media platforms want to imply via this feature so you keep engaged and stay on their platform and have to see more advertisements. But I don't see that for Phabricator (especially as we uninstalled the chat app Conpherence in T127640).
YMMV, of course.
(Note to myself: Opening the notifications dropdown and selecting Mark All Read reloads the entire page (but of course not any other Phabricator pages being opened).)