$ git clone -n https://src.fedoraproject.org/rpms/rust-gvdb.git /var/lib/mock/f40-build-2144116-50863/root/chroot_tmpdir/scmroot/rust-gvdb
Cloning into '/var/lib/mock/f40-build-2144116-50863/root/chroot_tmpdir/scmroot/rust-gvdb'...
$ git fetch origin 1284e76c4db00dbe17b6541e510a712616fff700:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gvdb
 * [new ref]         1284e76c4db00dbe17b6541e510a712616fff700 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1284e76 Update to 0.5.2 (rhbz#2235902)