Pick a proof file to check it. The file stays on your computer.
or
A pass means the file was not changed after the game made it, and the server stamps are real. It does not mean the player didn't cheat.
The mod runs on the player's computer, so a changed copy of the mod could lie. Only the official build is marked "Official build: yes". Always watch the video too. The dot in the corner of the video should match the clicks in the proof.
The proof can't catch input from hardware or drivers, or programs that change the game's memory from outside.