The freedom tools binaries are built for the Ubuntu 14 and CentOS 6 distributions:
If I wouldn’t want to build a toolchain just to build the toolchain, then I would use only available packages and ubuntu can be upgraded to gcc9 very quickly, while centos has limited options in upgrading gcc. Together with the glibc differences 2.12 vs 2.19. I would guess that the ubuntu variant is the recommended variant for most users while the centos is the fall-back compatibility variant where the ubuntu14 binaries will not work?
But don’t know if my assumption is correct, what is the reasoning for shipping binaries for these two distributions?