Docx (and pptx, and xlsx) is a zipped (not gzipped) composite of several XML files plus any other attached resources. It extracts out to a whole folder struct

Docx (and pptx, and xlsx) is a zipped (not gzipped) composite of several XML files plus any other attached resources. It extracts out to a whole folder structure. Definitely binary once compressed, though, and even when extracted not an easy format to parse. It might be XML, but it’s still representing the full complexity of an MS Office document.