Blocks sites via /etc/hosts. To unblock, you have to type a 40-character code from a piece of paper kept somewhere physically inconvenient. No paste allowed. It reads keystrokes one at a time and rejects anything that arrives too fast. Then a 5-minute countdown. Then yes. Then YES SIR YES.
The code is never stored in plaintext, only its SHA-256 hash. Lose the paper, run setup again, write it down again.
Also includes blokr watch: download a YouTube video locally via yt-dlp and watch it without the algorithm, sidebar, or autoplay.