libdontdie(7) on Linux
The text b6cfd16ee8cf, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch) shipped it. The page shows this text now.
a library that sets the TCP keep-alive flag when applications call socket(2)