$ git clone -n https://src.fedoraproject.org/rpms/gjs.git /var/lib/mock/f42-build-side-1-3587996-46941/root/chroot_tmpdir/scmroot/gjs
Cloning into '/var/lib/mock/f42-build-side-1-3587996-46941/root/chroot_tmpdir/scmroot/gjs'...
$ git fetch origin c9edb0351b4885a3fcef415a15f2cdaf4b65d527:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gjs
 * [new ref]         c9edb0351b4885a3fcef415a15f2cdaf4b65d527 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c9edb03 Bump release