$ git clone -n https://src.fedoraproject.org/rpms/rust-base64_0.13.git /var/lib/mock/f40-build-2679705-67934/root/chroot_tmpdir/scmroot/rust-base64_0.13
Cloning into '/var/lib/mock/f40-build-2679705-67934/root/chroot_tmpdir/scmroot/rust-base64_0.13'...
$ git fetch origin 31cb32107a8b2f53a572a7b42e28be60415175b5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-base64_0.13
 * [new ref]         31cb32107a8b2f53a572a7b42e28be60415175b5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 31cb321 Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild