This looks like a difficult situation. It seems we do not have any free
PIC headers. While the copyrightability of headers and (even more so) of
that XMl database is questionable, some jurisdictions have additional
database protection laws that could apply in this case.

Copyrights have considerable strength. Copyrights have advantages
as well  as it protects open source software from violations. It would
be a good idea to respect the copyrights on the header files. Be
careful about just duplicating headers. Rewritten headers may still
violate copyrights on the original material.

I am not a lawyer but this is an area that care needs to be taken.

 

Regards,

 

Walter Banks