It’s all in the main game log, and there are multiple possibly lines to parse:
LogNet: Join request: /Game/Maps/Startup?S (…)
LogNet: Join succeeded: Toolguy
ConanSandbox:Display: Character ID 3 has name Toolguy and guild ID 0.
that being said, I realize that there is no clear “player has left” entry in the log, other than the ones from the BattlEye module, maybe we shoyld add that, else it’s going to be hard to know when player left