Stefan because gimp and gimp-devel have different maintainer. And when gim 2.6 was out, only the gimp-devel maintainer update the packages. Then later gimp was updated too. But until new packages for development versions are out, the gimp-devel packages would be the same.

2008/10/24 stefan-husmann@t-online.de <stefan-husmann@t-online.de>

Hello,

why are there two packages gimp and gimp-devel with exactly the same
version number? Would one not be enough?

Regards Stefan