What is the `reader` parameter in URL commands?

I am creating some scripts to automate DEVONthink and DEVONthink To Go, and was wondering what is the reader parameter?

It is described this way:

reader: Post-process the page (integer, 0 = no post-processing, any other value = post-process).

but it doesn’t ring a bell.

BTW, I also wonder what is the referrer parameter, and how it would be used by DT and DTTG, especially if I provide the location as well.

The referrer is the URL without fragments like sections or user credentials. This is not a commonly used parameter.
The reader is how you use the clutter-free option.

I see. Where does it appear when you use this parameter?

What is the URL command to capture a clutter-free Markdown from a URL (location) then? Is this x-devonthink://createMarkdown?location=<…>&reader=1 ?