K,B,B Vs. K,B,KT in end game. who has the advantage?

It is hard to imagine that this is not a dead draw. Unless there are also some pawns.

White has the advantage, the bishop pair is stronger than the B+K. However the adventage isn't huge and the side with the bishop pair can't force a win. (There are obviously a couple of exceptions where the bishop can be won)

You have a weird concept of "advantage". Generally, chess delivers only 3 results: win , loss and draw. "Advantage" is an intermediate evaluation which is useful only when the situation is unclear or complicated. However this endgame is too simple to fall in those categories. It is just a draw except for special positions - the ones where you like blunder into a mate or serious  material deficit. StockFish rates all regular positions with this sort of material as dead draws (0.00).

🤡🤡🤡😀King bishop bishop Knight advantage

hm