screenruler(1) on Linux
The text ed0c463a4310, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy) shipped it. The page shows this text now.
a graphical ruler to measure objects on screen