The URL format of Stackoverflow is of the form .../id/question-title
If I add some more text at the end of the url like .../id/question-title-pink-unicorn and hit enter, the page is refreshed and the url is stripped of the pink unicorn I have just added. So far so good.
Then I change the url to .../id/question-title/persistent-pink-unicorn and hit enter, the page is refreshed and my pink unicorn is now a part of the url.
Edit: This doesn't look like a question although I submitted this via the Ask Question link. So here is the question. Will you allow my pink unicorn to reside on the site urls or this is something that should be fixed?