$ git clone -n https://src.fedoraproject.org/rpms/rust-fixedbitset.git /var/lib/mock/f39-build-1446048-32655/root/chroot_tmpdir/scmroot/rust-fixedbitset
Cloning into '/var/lib/mock/f39-build-1446048-32655/root/chroot_tmpdir/scmroot/rust-fixedbitset'...
$ git fetch origin d648d51addb96a1c211a8481ac623be088b1471e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-fixedbitset
 * [new ref]         d648d51addb96a1c211a8481ac623be088b1471e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d648d51 Regenerate with rust2rpm v24