As @Deltakosh points out the animations could be on the meshes. I’m not sure a 3 bone skeleton is necessary for opening a door (unless it somehow bends in the middle!). Here is an example :
Just click on the drawers and cupboard fronts. Click again to close them
As for your model, any attempt to play the animation results in “undefined” in the console. So if the file contains an animation - it is hiding somewhere.
The door just a test for understand how work, for learn how can I call animation and play.
Do you know why work on sandbox? In sandbox show all my animation states and work everything correct. Do you know if have a different method for get and play animations?
I would like to know too how can I play animation from the mesh without joints.