The Inspector complements the console, elements, and sources tab as a trusty companion as you build out your Marionette Apps.
You can use the Inspector to see what's going on under the hood with your ui, data, messages, and network.
Ofcourse, there's also a helpful 🔍 as well.
Etsy - The Inspector has largely been built as an open-source project at Etsy.
Backbone-Debugger - The Inspector is built on top of the Backbone Debugger core, written in large part by @Maluen.