dndbuster-rust/README.md

pdt - PleaseDisturbTimer

A timer that notifies you - even if "do not disturb" is enabled.

Alternatives

https://man.archlinux.org/man/notify-send.1.en

nix-shell -p libnotify

sleep 30m
notify-send -u critical -a PleaseDisturbTimer "Alert" "Time is over!"