Our dev group have found benefits in using the `postMessage` event as a great way to do pub/sub type communication. We'd love to use it in Launch, but don't see a way to make it work outside of Custom Code. Is Custom Code the only way to do it? It would be great to have an Event Type where we could select `postMessage` and then be asked for a string for it to look for inside of a data, so `siteEventName` in the example below. The data name would need to be standardized on, or also make that some...