We knew that the HomePod would obviously support Apple Music, and the specs listing on Apple’s website has revealed other audio sources which also includes iTunes music purchases, iCloud Music Library (which was previously confirmed), Beats 1 Live Radio, Podcasts, and audio sources that uses Apple’s AirPlay protocol.
While this does seem like a lot, it is actually rather limited due to the fact that many people get their music from a variety of different sources. For example some might download their music illegally, while others might use different streaming platforms like Spotify or Tidal, and not everyone listens to radio or podcasts.
However the speakers do support Bluetooth 5.0, but it is unclear if users will ultimately be able to use it as a Bluetooth speaker. This potentially means that if you don’t use a device that supports AirPlay, you won’t be able to play music via third-party sources, but we’ll have to wait for the device to be released to get a better idea.