$ git clone -n https://src.fedoraproject.org/rpms/librepo.git /var/lib/mock/f39-build-1515259-35649/root/chroot_tmpdir/scmroot/librepo
Cloning into '/var/lib/mock/f39-build-1515259-35649/root/chroot_tmpdir/scmroot/librepo'...
$ git fetch origin 8bca1010ecb93fe8505c3b1e1e12089425db760e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/librepo
 * [new ref]         8bca1010ecb93fe8505c3b1e1e12089425db760e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8bca101 Update to 1.17.0