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.
You wouldn’t phrase it like that. Android is based on Linux, and selinux is part of the Linux security subsystem. Android makes use of selinux features, among others, for security sandboxing.
Android also runs each app as a separate Linux user (separate UID). That, combined with SELinux sandboxing and the Android permission model, makes it a pretty secure OS.
Most modern androids enforce it btw