$ git clone -n https://src.fedoraproject.org/rpms/rust-unchecked-index.git /var/lib/mock/f40-build-2040434-48355/root/chroot_tmpdir/scmroot/rust-unchecked-index
Cloning into '/var/lib/mock/f40-build-2040434-48355/root/chroot_tmpdir/scmroot/rust-unchecked-index'...
$ git fetch origin 116f67dbf492604c81e4e39aeb913afae367945a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-unchecked-index
 * [new ref]         116f67dbf492604c81e4e39aeb913afae367945a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 116f67d Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild