$ git clone -n https://src.fedoraproject.org/rpms/gcc.git /var/lib/mock/f41-build-812377-147821/root/chroot_tmpdir/scmroot/gcc
Cloning into '/var/lib/mock/f41-build-812377-147821/root/chroot_tmpdir/scmroot/gcc'...
$ git fetch origin 4b5f87d836da79f7322915b8a9e2e4f08b828d0c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gcc
 * [new ref]         4b5f87d836da79f7322915b8a9e2e4f08b828d0c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4b5f87d 14.1.1-7