This page was loaded by a component specific override. You can use that - with care - if you have to implement custom loading strategies that are very local to the component. For instance, a custom component that loads it's template from a database and for which you don't want the application to have to know about it's differing loading resource.
This example loads the custom template just once, though it may reload when resource polling is turned on and the template changes. If you want a load the template every time a page (or panel) is requested, you can additionally let your container implement IMarkupCacheKeyProvider, and then return null in the implementation of getCacheKey; Wicket will not cache templates without a cache key. This functionality can be used to e.g. when you want to load templates from a database, and you know that the actual templates can be different from request to request.