Hello,
The Indexer class extracts contents (texts, links and images) from the comments of a DOCX: https://www.phpdocx.com/api-documentation/docxutilities/indexer-parse-word-documents-with-PHP
There's no method to analyze comments, but you could use getDOMComments, that returns the content of the comments xml file as DOMDocument and getDOCXPathQueryInfo to query by comment references to get more information about contents.
Regards.