Interesting (to me at least) to see the NSA in the list of contributors. Do they help out any other large open source projects?

SELinux is probably one of the most well known. They appear to have a technology transfer program[2], but i'm not sure that's been allowed in open source in any way. They have a Github repo[3], unless that's a hoax of some sort. It seem legit on a very cursory glance. Other google results seem to indicate the projects in that repo are named the same as some projects the NSA has open sourced publicly.

I imagine they contribute bits and pieces to quite a few projects that they use in-house.

1: https://en.wikipedia.org/wiki/Security-Enhanced_Linux

2: https://www.nsa.gov/what-we-do/research/technology-transfer/

3: https://github.com/NationalSecurityAgency

amazon is one of the biggest xen player but does not contribute, so sad.