the black advantage

where is it coming from
black has an advantage which is plus 1 for black if white moves first and black has an advantage of about plus 1.5 for black if black moves first. I thought that black only has the first move advantage until I swapped who moves with the analysis board and the engine
I also swapped the rook and the bishop and it didnt explain it either. the chequemate in 1 puzzles are too hard!

oh yes, reallyÉÉÉÉÉ

If I’m right, the advantage black has is taken care of by the glicko2 rating system used by lishogi.