$ git clone -n https://src.fedoraproject.org/rpms/rust-derive_builder_core.git /var/lib/mock/f40-build-2081596-49776/root/chroot_tmpdir/scmroot/rust-derive_builder_core
Cloning into '/var/lib/mock/f40-build-2081596-49776/root/chroot_tmpdir/scmroot/rust-derive_builder_core'...
$ git fetch origin cf0096e9f304875590478c29c3af1cfc6da37f1d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-derive_builder_core
 * [new ref]         cf0096e9f304875590478c29c3af1cfc6da37f1d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cf0096e Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild