This feature is intended to remove the unneeded parameters from canonical links to tell the search engines that they should not index them.
Once DJ-Canonical is enabled, go to your website frontend.
Now, reload your website and check its source (right-click -> "View page source"), there you will see:
and even if your website is available from addresses like:
If you're using the feature "Cut parameters" you can also test it by adding any parameter to your URL or visiting it from a shared link on Facebook.
Your url once visited from the Facebook link will look something like this:
but the canonical link in the source will still be: