A recent change ensures that Assets always use a complete URL, not a relative URL. This means that Assets are, once again, invariant. Therefore, we should (in most cases) allow Assets to be invariant again.
However, for the tapestry-templating (an external project) it is necessary that Assets be invariant, because an Assets path will vary from request to request, based on the location. So, we should have a configuration symbol to control whether Assets are invariant or not.