Security-enhanced Linux is a feature of the Linux® kernel and a number
of utilities with enhanced security functionality designed to add
mandatory access controls to Linux. The Security-enhanced Linux kernel
contains new architectural components originally developed to improve
the security of the Flask operating system. These architectural
components provide general support for the enforcement of many kinds of
mandatory access control policies, including those based on the
concepts of Type Enforcement®, Role-based Access Control, and
Multi-level Security.

libsepol provides an API for the manipulation of SELinux binary
policies. It is used by checkpolicy (the policy compiler) and similar
tools, as well as by programs like load_policy that need to perform
specific transformations on binary policies such as customizing policy
boolean settings.