What collision model is used?

There use to be a option to show the Collision skeleton for an Avatar but has been broken since Havok 4.

So now I am trying to figure out what collision model it uses when an AV it is sitting. or what ever the AV is doing. When sitting it appears to use the default sit is used as the collision even if your pose change. Is any part of the Uploaded pose used at all in figuring what the collision will be for the AV? such as the first reference frame?

Okay so after much testing. The conclusion I can come up with:
The collision model SL uses resemble something like the generic sit when an AV sits on an object. my little experiment I have post here