Only DRM free content. Probably not what you want your fancy internet connected speaker to play.
What is DRM free content?
Everything you can get a direct file link to. It needs to be without a login, hosted on the internet or your local network.
This excludes most streaming services like Netflix or Spotify, since you cannot get a direct link (.mp3/4) and have to log in.
However most radio stations have direct links and don't need a login.
What formats are supported?
Almost every major format is supported. A full list is available by Google.
How do I create presets?
Use the preset generator. A guide is available.