Where the water line starts for sprite physics
Only used for BG3 tilesets $13 (value $07B0) and $1D ($0700)
Value is left at $4000 when disabled
This doesn't affect regular water objects, only hardcoded water for certain BG3 tilesets.
ss = vertical screen number
yy = Y-position of water line
Timer for Yoshi turning pose. Starts at #$0004 when you change direction while in movement (ground or air), remains with this value for a brief time if you keep holding this direction until it starts decrementing each frame.