Sorry, the message was sent while I was editing and it appears I cannot edit the body. The issue is that in the worker editing console window the site shows normally as should, but not anymore in a browser. In the editing console window the Content-Type header is set as should, but for the browser it’s always text/html and I don’t seem to understand why is that. I have cleared the cache (and set development mode on), cleared browser cache etc., but nothing seems to help.
Is there something obvious that I don’t understand? It appears I can set new headers and they show in the output.