I've removed the comment because it doesn't have correct formatting and moved it as the "answer".

Thank you for the response and your time. Hm… the preview isn't very important, but I forgot about plugin preferences (each plugin can define its own preferences). I think I could create a dedicated type to describe how preferences should look like and pass them to the app. And the preview could be a simple screenshot/image provided by the plugin author. Another option is to use WebKit and web technologies – the xpc app would present the WKWebView and handle some JS events (I'm thinking loudly) but I guess it's beyond my knowledge how to it right. Thank you again!

@Frameworks Engineer I also have autolayout issues, not resolved from the first beta. I have two apps with quite significant UI issues because of it. FB13365992

@Frameworks Engineer I made another radar: FB13365992