Is it possible to modify discovery.xml?

There’s a section in the SDK named modifying discovery.xml, but the section only talks about what the URL means and nothing about modifications, so is it possible to customize the URLs? For example, let different file types and actions use different URLs.

What you could do is restrict actions on file types, ie. edit → view_comment / view (though I’d say it’s more logical to do that on the integration side, as also the list of file types CODE/Collabora Online can open doesn’t necessarily mean you’d want to allow opening all those files).
Customizing the URLs isn’t an option.