wn_set_pretty_linefeed_routine(3) on Linux
The text 6326a8b90b67, as Debian 4.0 (Etch), Debian 3.1 (Sarge), Debian 3.0 (Woody), Debian 2.2 (Potato), Debian 2.1 (Slink) shipped it. The page shows this text now.
write stuff pretty, with lines no longer than some fixed length