TEXP is essentially experience that you earn in game. So when you kill a mob or mine a coal ore and gain experience, TEXP goes up. Not completely sure what the "T" stands for though.
800 "TEXP Points (xp orbs)" is when you get to level 30 ( Not just EMC, universal minecraft xp logic) So you have gotten to level 30 about 48.5 times (From Phone's TEXP stats)