[CentOS] redistribution of isolinux binaries

I've been making my own custom RHEL / CentOS boot CDs for years,
and all of the instructions for such work call out to take a distro's
CD, and copy key files from it.

Among those files are those that I think are associated with the
the SYSLINUX/ISOLINUX project; e.g.:

  http://mirror.centos.org/centos/6/os/x86_64/images/
  http://mirror.centos.org/centos/6/os/x86_64/isolinux/

Two questions:

- As the SYSLINUX project is GPLed, to hand out binaries implies
  the sources are available somewhere, but I can't find an official
  point of reference on where the corresponding sources are.

- Further, near as I can tell, the SYSLINUX project makes no reference
  to Kickstart, but I do see Fedora refer to Kickstart:

    https://fedoraproject.org/wiki/Features/SyslinuxOption

  This has me wondering if Fedora maintains local changes to the
  SYSLINUX project.  If it does, that further lends to my interest
  in tracking down the utilized sources.

Does anyone have any insight on these topics, or, at the very least,
a better forum to pursue them?

-- 
Brian Reichert				<reichert at numachi.com>
BSD admin/developer at large