User Data

Optional. Enable any of these values by adding it to the profile and setting it equal to "on."

discard-comments-forms-multimedia	Removes interactive elements from the PDF document. These can include annotations, such as pop-up notes, comments, and highlights, as well as interactive Acrobat form fields and embedded multimedia. Besides removing the interactive elements, this option also removes the visual content associated with these elements.
discard-xmp-metadata-padding	XMP refers to the Extensible Metadata Platform, a standard created by Adobe Systems to guide the creation, processing, and exchange of metadata for a variety of digital resources. When XMP metadata is included in a PDF document, the application that creates the PDF leaves a “padding area” in the text stream, commonly 2 to 4 KB for each set of XMP metadata. This allows for the metadata to be edited in place, and expanded if needed, without disturbing the document as a whole. This option removes the XMP padding from the document.
discard-document-information-and-metadata	Removes document descriptions and metadata
discard-file-attachments	Removes files attached to the document
discard-external-crossreferences	Removes references to external data. This would include links to external resources, like a photograph or another PDF document that could be downloaded from a web page or FTP site. This option effectively removes the hyperlinks to these items.
discard-private-data	Removes piece data relevant to the application that created the file. Some applications, like Adobe Illustrator, add their own unique content to a PDF document when generating that document. This information is useful to the original software product if the PDF is opened and edited in that product again. But this information can be removed.
discard-hidden-layer-content	Layers in a PDF document allow content to be placed above or below other content. The content in layers can be hidden from view, so that, for example, copyright information provided on the bottom of a page does not appear in Adobe Reader but is included if the document sent to a printer. The layers in a PDF document can be displayed in the Layers panel in Adobe Acrobat. You can remove this hidden content to reduce the size of a PDF document.

}
. . .
    "userdata": {
        "discard-comments-forms-multimedia": "off",
        "discard-xmp-metadata-padding": "off",
        "discard-document-information-and-metadata": "off",
        "discard-file-attachments": "off",
        "discard-private-data": "off",
        "discard-hidden-layer-content": "off"
. . .
}

Compressing PDF Files