The Schuhler Gambit is a line in the Sokolsky Opening.
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1. b4 c6 2.Bb2 a5 3.b5 cxb5 4.e4
White gives away their b-pawn here. Stockfish claims this actually gives a small advantage to White, (although I analyzed only to depth 25) while bxa5 gives a small advantage to Black.
Why is it good and what is White's plan?