What is the meaning of the prepended "rh-" in some of the scl RPM names? At first I thought they were rebuilt from official upstream RHEL rpms, but it appears non "rh-" prepended ones are, too.

Which leads me to wondering who is the original upstream for packages in the sclo/x86_64/{sclo,rh} directories? Is the rh directory that which contains RPMs blessed by RH (as in, they provide support for) but which exists to centos users as a rebuild of the official RHEL RPMs as all the base packages generally are?

I know that as a centos user, the upstream for the purpose of support and bug submission is never RHEL, so my question re: upstream is more of a point of origin question, I guess.

Thank you for your time