Quick Look Preview Extension

I'm trying to add a quick look preview extension to my app.
But
I can't find any reference on this
On a earlier thread (https://developer.apple.com/forums/thread/704155)
everyone seems to misunderstand my question.
I MEAN THE QUICK LOOK YOU CAN TOGGLE IN FINDER THAT WILL SHOW YOU A PREVIEW OF A DOCUEMNT
I don't want to add the tag QuickLook because that's not I want to do.

There are two ways to see a preview of a file in the Finder.

  1. Select the file and tap the Space bar.
  2. Select the file, do Get Info (command-I) and then open the Preview section of the info window.

Both of these methods use the same Quick Look extension mechanism, so I think it is you who has misunderstood.

Quick Look Preview Extension
 
 
Q