$ git clone -n https://src.fedoraproject.org/rpms/rust-cargo.git /var/lib/mock/f40-build-1780527-24818/root/chroot_tmpdir/scmroot/rust-cargo
Cloning into '/var/lib/mock/f40-build-1780527-24818/root/chroot_tmpdir/scmroot/rust-cargo'...
$ git fetch origin 0c6cc1f5a9a3928d0cab59c88c77d0052bf3fd72:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-cargo
 * [new ref]         0c6cc1f5a9a3928d0cab59c88c77d0052bf3fd72 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0c6cc1f Update gix dependency to 0.63