what is the max limit of bone count for one model?

First of all, I am asking the max bone count, not the bones count for influencing a given vertex, or bone count for skin weights.

I have googled a while, and found some old topic like:
How many bones? -- https://forum.unity.com/threads/how-many-bones.205650/


In my game I was using gpu skin, while some model have 30 bones, and some have up to 120 bones. I was wondering What is The Max Bone Limitation For One Model In Unity? Is it related to gpu registers or uniform count? or something else?

It is very helpful if I can get one exactly number, for performance and both for artists creation.

 

Still no answer. I would like to use bones to Batch a lot of stuff into one model (Instancing and dynamic batching won't work).