I use it in combination with a trap on DEBUG signal to compute information about each interactive command (start/stop timestamps, type, working dir, return code

I use it in combination with a trap on DEBUG signal to compute information about each interactive command (start/stop timestamps, type, working dir, return code, and more) and save it in a big log file. I can then transform the data into pretty charts! It's also used by the `z` command line tool to maintain its directory "frecency" list.