I'm not totally sure what syntax we're using in our own node stuff (I don't think it's exactly the same as Inspector.json), but from looking at other examples in our own code (e.g. StaticServerDomain) it looks like the results list is supposed to be an array with one entry for each callback argument (excluding the error arg); and if the argument is an object, the structure of the object is just listed in the type of the argument, rather than broken out as we're doing right now. So, for example, assuming we don't actually change the return args, our docs for the return of `extensionManager.install()` should be:
```javascript
[{
    "name": "result",
    "type": "{errors: string|Array.<string>, metadata: {name: string, version: string}, disabledReason: string, installedTo: string, commonPrefix: string}",
    "description": "...(docs for all the object members)..."
}]
```