Red Hat Enterprise Linux is a Linux distribution produced by Red Hat and targeted toward the commercial and enterprise market.
Red Hat Enterprise Linux is often abbreviated to RHEL. New versions of Red Hat Enterprise Linux are released every 18 to 24 months.
Note: Verbatim copying and redistribution of the entire Red Hat Enterprise Linux distribution is not permitted due to trademark restrictions (source: Wikipedia).
Some pointers, for those developers who need to interact/collaborate with RedHat RHEL package maintainers.
RHEL Product Homepage: Red Hat Enterprise Linux
Information about package/projects: TBC
Find source packages: ftp.redhat.com
Find binary packages: TBC
Bug Fix Advisory Tracker: Red Hat Product Errata - Bug Fixes
Security Advisory Tracker: Red Hat Product Errata - Security