$ git clone -n https://src.fedoraproject.org/rpms/librepo.git /var/lib/mock/f40-build-1561166-23993/root/chroot_tmpdir/scmroot/librepo
Cloning into '/var/lib/mock/f40-build-1561166-23993/root/chroot_tmpdir/scmroot/librepo'...
$ git fetch origin 1a8e1d86bbcc8754f501146c9bfe61faeae59f94:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/librepo
 * [new ref]         1a8e1d86bbcc8754f501146c9bfe61faeae59f94 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1a8e1d8 Update to 1.18.0