I made a slight change to the draft API at [1]. I modified the |type| attribute to be a ContentTypes instead of ContentType.
ContentTypes [2] is a comma-separated list of media types.
One use case for this change is an image editor that would ideally register for image/* but cannot due to limitations in the libraries used to encode/decode images; therefore, they will now register for, e.g., "image/png, image/jpeg"
Thanks,
James