I’m glad Brownie was there to help you!

And anything with the air system is confusing enough to me that I’d leave it to others, so good on you!

docx is OOXML, Open Office XML.

However, it was definitely written to ensure existing doc files could be fully supported, so a lot of the format is “bit 7: if enabled, use Word for Mac 5.0 layout engine.” So… Documented, yes. Usable, no.

PDF, as mentioned, is very similar. The format is available, but no one really wants to implement ALL of it.