$ git clone -n https://src.fedoraproject.org/rpms/GraphicsMagick.git /var/lib/mock/f41-build-854752-166955/root/chroot_tmpdir/scmroot/GraphicsMagick
Cloning into '/var/lib/mock/f41-build-854752-166955/root/chroot_tmpdir/scmroot/GraphicsMagick'...
$ git fetch origin 115f924542115e9bed78a4b872781f851f58ba71:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/GraphicsMagick
 * [new ref]         115f924542115e9bed78a4b872781f851f58ba71 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 115f924 Update to 1.3.45