Called when the game(server) needs to update the text shown in the server browser as the gamemode.
sv_gamename_overridecommand) may not work on some popular gamemodes like DarkRP or Trouble Terrorist Town. This is not a bug, it's just how it works. See here for more information.
Also, it only works on dedicated servers and is called at regular intervals (about one second) even if the server has no players and the hibernation function is enabled.