I didn't know about that and it's almost exactly what I want. When did that get added? Clever hiding it under a single-option "Generate" submenu.
It even supports svg shapes and exporting sub-layers alongside containing groups. Definitely the best way to do multi layer exporting.
I still need the positions and structural hierarchy so it's not quite enough for the Mars case but I'll put it in the toolbox for other projects. Thanks for pointing it out :)