$ git clone -n https://src.fedoraproject.org/rpms/alt-ergo.git /var/lib/mock/f39-build-2074097-49409/root/chroot_tmpdir/scmroot/alt-ergo
Cloning into '/var/lib/mock/f39-build-2074097-49409/root/chroot_tmpdir/scmroot/alt-ergo'...
$ git fetch origin 17e8a91f5087c14bd5ce2be2af1b5ca82b7c86ed:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/alt-ergo
 * [new ref]         17e8a91f5087c14bd5ce2be2af1b5ca82b7c86ed -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 17e8a91 Rebuild for ocaml-zarith 1.13