Posted by gpi 13 hours ago
https://marc.info/?l=openbsd-ports-cvs&m=121226747005033&w=2
I had discovered it searching on SourceForge originally, but the tmux creator Nicholas Marriott was already an OpenBSD user and he took MAINTAINER for the port.
A year later, tmux was imported by nicm@ to the OpenBSD base system, and has remained the upstream for 16 years (GitHub sync from OpenBSD).