A .docx is an archive of plain XML
Rename a copy to .zip and open it and you can read the properties in any text editor. One file holds the author, the last person to save it and the revision count. Another holds the company name from the Office licence and the total minutes the document has been open for editing across its life.
Total editing time tells a story
A proposal that claims weeks of work and reports eleven minutes is one story. A contract with an enormous editing time, suggesting heavy internal negotiation before the other side saw it, is another. Neither is something anyone means to disclose.
Tracked changes are content, not metadata
Insertions and deletions live in the document body, attributed by name and timestamped, with the deleted text retained alongside them. Turning off the markup display hides them from you and from nobody else, which is how internal positions reach the people they were being hidden from.
Comments live in their own part of the file
Reviewer comments are stored separately from the text and survive being collapsed in the interface. A document can have no tracked changes and still carry a dozen comments, or the reverse, so a tool that reports one and not the other gives false reassurance.