The NSA, the original primary developer of SELinux, released the first version
to the open source development community under the GNU GPL on December 22,
2000.[6] The software was merged into the mainline Linux kernel 2.6.0-test3,
released on 8 August 2003. Other significant contributors include Red Hat,
Network Associates, Secure Computing Corporation, Tresys Technology, and Trusted
Computer Solutions.
https://en.wikipedia.org/wiki/Security-Enhanced_Linux
[https://en.wikipedia.org/wiki/Security-Enhanced_Linux]