$ git clone -n https://src.fedoraproject.org/rpms/rubygem-rspec-mocks.git /var/lib/mock/f38-build-side-42-init-devel-724559-27307/root/chroot_tmpdir/scmroot/rubygem-rspec-mocks
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-724559-27307/root/chroot_tmpdir/scmroot/rubygem-rspec-mocks'...
$ git fetch origin 73e82a735096e706a016dd103a433b9393552fe9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-rspec-mocks
 * [new ref]         73e82a735096e706a016dd103a433b9393552fe9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 73e82a7 3.12.5