The Automatic Rule-Based Time Tracker is a desktop daemon that runs in
the background and, every minute, records what windows are open on
your desktop, what their titles are, which one is active. The
accompanied statistics program lets you derive information from this
log file, i.e. what how much of your time have you been spending with
e-mail, or what projects are your largest time wasters. The mapping
from the raw window titles to sensible "tags" is done by a
configuration file with an powerful syntax.

WWW: https://arbtt.nomeata.de/