It's a guy that is in between both of the people..... He/she makes sure the trade goes how it should go, 100%Scam Free and 100%Smooth, he is the one that also provides accurate proof incase one of the guys decides to scam, which in my opinion is completely stupid...... More detailed information about that is here:
https://www.mpgh.net/forum/125-middle...n-process.html