Extracting model from workshop player model?

I’d like to extract the data / the model from my old avatar I uploaded to the workshop and have since lost the source to.

If there’s any tooling to help with that it’d be appreciated.

A full (or even partial) specification of the format would also help, and I could probably get by just knowing how the index buffer, vertex buffer, and material sections work.

The model is version 1 of the format, unsure how much that changes.

Thank you!