Displaying the result was buggy: if there was an error/warning, nothing was displayed (which is incorrect, there may be no template file, but that is only a warning).

B.t.w.: there should be a difference in the error replies on whether it is a warning or an error
The (output) format setting was buggy: the user's required setting should take the upper hand.
A first round works with the default mapping: both JSON and RDF are generated with, currently, only the few top level infos