Although the original code was published by the NSA, RedHat and several other groups and companies have been involved in SELinux development over the past 12+ y

Although the original code was published by the NSA, RedHat and several other groups and companies have been involved in SELinux development over the past 12+ years. The paranoia of having a backdoor in SELinux (very unlikely) has probably made it a more frequent target of audits compared to other parts of linux.