Does the free version work at all with JSON API?

I've installed the plugin, enabled it, set "Enable Authentication" and "API Key Authentication", and generated a key.

By default, it appears that it should now manage jsonapi endpoints. But any request to /jsonapi/node/my-content-type, using a header of api-key=yaddayadda, yields "Some resources have been omitted because of insufficient authorization."

Am I missing something basic here?

Update:

I realized that I needed to provide a full BasicAuth description even when it's set to "API Key Authentication", and that since the key is global in the free version, I could use any username as the prefix. This could probably stand a little better documentation.

That said, I have no evidence that the plugin actually acts on `/jsonapi` requests.