First, let me just say I've really been enjoying using api-extractor. I was struggling for days getting anything to work in TypeDoc, but got a proof of concept working with api-extractor in less than an hour.

I'm currently playing around with generating API documentation for Glimmer.js and piping the JSON into a Glimmer app that renders it:

One limitation I've run into is that it's not possible to extend AEDoc annotations with additional metadata. For example, we want to be able to group methods and properties by "topic" instead of one big list per class. I'd like to be able to do something like @topic Lifecycle Hooks to indicate which topic a class or interface member belongs to.

I'm sympathetic to the design goal of precise parsing, but would you be open to some sort of configuration that whitelists additional annotations in comments, which would get included in JSON output?