I think it was mostly Zenva rushing to get some sweet cash while the drama and popcorn around Unity are still hot. HumbleBundle being anything but humble of course would set it up ASAP, I bet the charity was decided from a random wheel they keep around.
I hazard this guess because most other Zenva bundles offer Unity and/or Unreal courses. Also, a large portion of those Godot videos are “HumbleBundle Exclusives”, so stuff that they likely haven’t finished yet