I was building a belt from the surface down to the cavern. Placing down the belt made the game crash and gave me the following error message:
Error while running event subterranio-base::on_built_entity (ID 6)
Missing specification of animation with name: "mineshaft-belt-graphics"
stack traceback:
[C]: in function 'draw_animation'
subterranio-base/scripts/entity/mineshaft-belt.lua:37: in function 'built_mineshaft_belt'
subterranio-base/scripts/event-handler-combinations.lua:36: in function <subterranio-base/scripts/event-handler-combinations.lua:33>
Hopefully it gets solved soon, because I really like the idea of caves and caverns.