What OOXML layer does Acrobat use to store Table of Content (ToC) anchors in a converted Word doc?

[Kevin2726607167cq]

In what OOXML layer does Acrobat Pro store Microsoft Word Table of Content anchors?

I converted a large PDF (which itself was probably created originally in Word) to a Microsoft Word .docx file.  The docx file now contains annoying "Table of Contents" anchors throughout.

As I edit the docx file, the ToC anchors do not move, staying right where they originally were copied, thus they are some kind of OOXML object other than text.

I cracked open the docx file to view the underlying OOXML / XML files, but there is no text string "Table of Contents" for ToC anchors anywhere to be found.  My guess is that the ToC anchors are either an object (like bookmark, watermark, or graphic) and I need to remove them all now.  Can't find them even in the foundational OOXML files.