$ git clone -n https://src.fedoraproject.org/rpms/zchunk.git /var/lib/mock/f41-build-819568-151695/root/chroot_tmpdir/scmroot/zchunk
Cloning into '/var/lib/mock/f41-build-819568-151695/root/chroot_tmpdir/scmroot/zchunk'...
$ git fetch origin 2be4318ea8233299707a44aee12d7432aecb8e70:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/zchunk
 * [new ref]         2be4318ea8233299707a44aee12d7432aecb8e70 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2be4318 Fix memory leak