Cool, I've edited the thread title accordingly.
6. Additional lock types
The lock request and management mechanism presented in this document can be extended to support additional types of locks by adding new lock request flags to Document interface. E.g. a "system" wake lock could be introduced which would prevent the device's cpu, radio(s), and other system services from entering a power-saving state while allowing the screen to switch off.
This should actually be specified as part of the draft, since Chrome already has support for it, and pages like music sites have a need for it. (If you need an example for something that's not ready yet, you could use "lid", for keeping the screen awake even when the lid is closed, as is being discussed at https://code.google.com/p/chromium/issues/detail?id=287071.)
What about recommendations for the UX for tabs that implement this? Can that be a non-normative section of the spec?
Also, how should a polyfill extend an evented property-getting-and-setting API like this? Should it call