In the past, while using Elm, if you wanted to support some browser API that Elm didn't support yet you would have to fallback to kernel code. What Elm wanted: a core package that provided this low-level kernel package that provided typesafety at the Elm level. But as we know, this was a pipe dream because you could never contribute to Elm unless it was from the Elm dictator itself, or from his inner circle of cool people.
It seems like Gren is already ahead of this. Gren has community members actively working on the Websocket API to provide a typesafe core package with Kernel bindings.
The question is: will Gren keep being open to contributors that can provide kernel code.