Suggestion: it would be helpful if the website stated what the purpose of the extension is first. It jumps right into installation... I'm only at the point where I want to decide if I need this extension or not.
We use a Map and Set polyfill for most browsers, so if the store contains Map's or Set's, they are opaque blobs to the dev tools. It would be awesome if, instead, expanding an iterable would get all the values and then display them as if it it were an array (for Maps it would be an array of tuples). This should be optional, as iterators could have side-effects or be infinite.