I just noticed a Thunderbolt software project on 01.org, the Intel Open Source project site:
The last release was a few months ago. However, this is not a normal open source project. It is “restricted open source”, only only for Thunderbolt vendors, not the public.
The code can be accessed from the restricted Git Hub at: https://github.com/01org/thunderbolt-software
An access can requested at email@example.com only for manufacturers having a valid Thunderbolt technology license.