TEST
I'm just experimenting with baked lighting and glass in Sketchfab.
Notes:
Add a transparency node when baking glass in Blender, to avoid the harsh black shadow underneath the glass.
Glass still works in shadeless mode.
For the baking, I used Combined pass on the Scene objects, and Glossy Indirect Color pass for the glass. I combined them in Gimp and used them as the Albedo texture.
I converted the Glossy pass to BW, adjusted it with curves, and put it into the Albedo alpha channel for reflection opacity.