Some of this metadata had issues, and presenting both the old individual extension releases and the new unified releases tends to confuse people. So, simply remove it; a summary of changes that old aren't really useful to anyone now anyway.
This doesn't work because lv2_check_syntax.py uses serdi, and so would need to call it with a wrapper. That's possible (and is how the test scripts work), but this check doesn't need to run everywhere, so just disable it in cross builds to avoid the issue.