SirenWard от qwertyopy

SirenWard is an open-source browser extension against digital distraction. It combines site blocking, a calmer YouTube (like Unhook), channel and keyword filters (like BlockTube) and a lock mode you can't simply switch off on a whim.

Privacy first: no servers, no accounts, no tracking, no history. The extension has no technical way to send data – its content security policy forbids every network connection.

Works in Chrome, Brave, Edge, Vivaldi and Opera (version 120+) and Firefox (128+).