Yeah but it’s like saying, “why are you impressed with Claude making a car when there are plans for an engine online?”. Even if Claude used that code (it didn't), it made the whole car. Not just an engine. There’s a lot more stuff going on than simply calling a backend mail server over jmap.

And fyi, jmap is just a protocol for doing email over json & http. It’s not that hard to roll your own. Especially in a web browser.