who’s the target audience for this? just curious

rails & django people?

Seems like it's anybody who wants to just use native js features without complication. Anybody who's been writing modern js and is aware of all it's features has probably had the thought "oh we really don't need almost any of this shit with the web native features we already have, we just need to teach people about those existing features."

Arrow-js looks like it's basically advocating for not using anything but vanilla js by tricking you into thinking it's a framework / lib. I mean, it is that, but it looks like it's barely that, and just sorta shows off how you can use vanilla js features to accomplish what all the various libs do, without introducing a lot of special lib-specific concepts.