Is 6. ... Bg4 line instead of 6. ... Bd6 a better theoretical line or just a Stockfish nonsense?
http://lv.lichess.org/sBjaHCUP/black#12Actually, let's not be smug and expand on that. :P 6..Bd6 is not a theory line because the intended dxe5 fxe5 fails to Nxe5! Bxe5 Qh5+ forkins, and dxe5 Bxe5 Qxd8 Kxd8 Nxe5 doesn't need any comment on why black is much worse.
After 5..f6 6 d4 the theory lines are exd4 and Bg4, though I personally prefer the 5..Bg4 lines... but it's all good.
I usually play d6 after Bb5