Interesting and the nice thing about him wanting to add JavaScript runner support is the JRE does have a JS engine you can embed into your apps.
The JS runner in Postman felt a little limited I couldnt for example figure out how to fetch a document.cookie from a response. It would be awesome if the JS runner can match the usefulness of the one from Postman in addition to being extendable like the rest of Milkman seems to be.
One thing I wish there was and maybe this project might be extensible towards is a JMS / better ActiveMQ / JMS client.
I personally switched to vscode rest client some time ago because the requests are just text on the filesystem so clearly visible in code review etc, but this looks really promising