$ git clone -n https://src.fedoraproject.org/rpms/gthumb.git /var/lib/mock/f41-build-815465-149534/root/chroot_tmpdir/scmroot/gthumb
Cloning into '/var/lib/mock/f41-build-815465-149534/root/chroot_tmpdir/scmroot/gthumb'...
$ git fetch origin f3e0b930a536be58dc0eddef4d98c1c4f803dea8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gthumb
 * [new ref]         f3e0b930a536be58dc0eddef4d98c1c4f803dea8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f3e0b93 Rebuilt for exiv2 0.28.2