$ git clone -n https://src.fedoraproject.org/rpms/kollision.git /var/lib/mock/f40-build-2006171-45143/root/chroot_tmpdir/scmroot/kollision
Cloning into '/var/lib/mock/f40-build-2006171-45143/root/chroot_tmpdir/scmroot/kollision'...
$ git fetch origin d654ace6e676a83dd31fd42ae8f37ed651994aeb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/kollision
 * [new ref]         d654ace6e676a83dd31fd42ae8f37ed651994aeb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d654ace Update sources file