There were no commit messages. Since 2002, the change were pushed on a public server with nightly snapshots. At some point, there was a changelog, but it didn't last long.
Brantley Coile noticed the Plan 9 trademark expired and bought it on November 25, 2020.
It was before the transfer of the Plan 9 copyrights to the Plan 9 Foundation (March 23, 2021).