bidentd(8) on Linux
The text 4d4be21c88fd, as Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy), Debian 6.0 (Squeeze) shipped it. The page shows this text now.
Bisqwit's TCP/IP Identification Protocol daemon
Flags it lists
-
-q -
-qq -
-v -
-vv -
-vvv