DISCOVERY-API is used as an example of features affording the "ability to access information about other devices to which a user has access". Clicking through the links takes you to Network Service Discovery, which has no content apart from boilerplate and a notice indicating the API proposal has been with withdrawn:

Work on this document has been discontinued and it should not be referenced or used as a basis for implementation.

Since there's nothing there now to illustrate why this API would have been a good example, it seems like it should probably be removed or replaced.