How to use Devel module to see what creates an URL?
Not really sure what you are meaning by 'create url', but any url in Drupal is registered through hook_menu(). Don't let the name confuse you - this is a seperate concept to lists of urls (like the navigation menu). The menu system keeps a cache of url to callback function mappings, which you can inspect to see which function each url points to.

To view the menu cache, you can run this code:

dpm(menu_router_build());


You can then look through the array to see the details for each url.