I just noticed a Thunderbolt software project on 01.org, the Intel Open Source project site:
https://01.org/thunderbolt-sw/blogs/mjamet/2015/thunberbolt-software-15.32
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 thunderbolt-linux@intel.com only for manufacturers having a valid Thunderbolt technology license.
https://01.org/thunderbolt-sw/
https://github.com/01org/thunderbolt-software
https://lists.01.org/mailman/listinfo/thunderbolt-software
https://thunderbolttechnology.net/
https://thunderbolttechnology.net/news/press