From: me@prestoncrawford.com
They could not do the latter as far as I understand it. Because Fedora Core is not the source code (letter for letter) of RHEL.
From: "Bryan J. Smith b.j.smith@ieee.org"
Every RHEL package as a 1:1 version to Fedora, typically Fedora Core, possibly Fedora Development (as it seems MySQL 4 was). This is fact. Nothing goes into RHEL without going through Rawhide/Development first -- if not into Fedora Core. If you read Red Hat's own development and lists, packages that have "EL" are typically subsets of the FC version. Most of the time, it's due to locale -- Red Hat strips out unsupported locale. In other cases, there might be supersets, like the kernel. In those rare cases, yes, Red Hat needs to redistribute those source changes.
BTW, assumptions such as yours is entirely based on "branding." It's a common thing that people do, and goes to the heart of the trademark matter, as well as gross mis-representation and lack of attention to detail by many.
People assume something is "Red Hat(R) Linux" because the "Red Hat(R)" trademark is on it. They assume it is completely different if the trademark is not. It doesn't matter if completely modified packages for an architecture Red Hat never supported, and the packages are even completely SRPM _incompatible_, people believed it was still "Red Hat(R) Linux."
Ironically, people assume "Fedora(TM) Core" has nothing to do with "Red Hat(R) Enterprise Linux" -- or is at least completely different in its relationship with RHEL than "Red Hat(R) Linux" was -- merely because of the "branding." In training courses, I've taken people completely through an entire rebuild of core packages, down to version, of Fedora Core and Red Hat Enterprise Linux, as well as SuSE Linux and SuSE Linux Enterprise Server, and it's amazing to see that FC and RHEL differ far less than SL and SLES.
If the RPM version is the same for a package of Fedora Core and Red Hat Enterprise Linux, they _are_ the same from the standpoint of GPL source code. Things that are modified have "EL" attached to the version, and in many cases, it's actually a locale subset consideration for RHEL.
-- Bryan J. Smith mailto:b.j.smith@ieee.org