SimpleAgenda(1) on Linux
The text fd5c9108fbe2, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 7 (Wheezy), Debian 6.0 (Squeeze), Debian 5.0 (Lenny) shipped it. The page shows this text now.
calendar manager for GNUstep