This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
The HTMLSourceElement's IDL keysystem attribute needs to be explicitly defined to reflect the keysystem content attribute. So I suggest we change this text in the spec: "The keySystem attribute of HTMLSourceElement specifies the Key System to be used with the media resource. The keySystem attribute must be supported by all HTMLSourceElement as both an IDL attribute and also a content attribute named keysystem." to: "The keySystem attribute of HTMLSourceElement specifies the Key System to be used with the media resource. The keySystem attribute must be supported by all HTMLSourceElement as both an IDL attribute and also a content attribute named keysystem. The keySystem IDL attribute must reflect the keysystem content attribute."
Fixed in https://dvcs.w3.org/hg/html-media/rev/129bbc12747a. I rewrote the definition text for the two attributes to be more similar to the HTML5 spec and correct references to the wrong attribute.