Previewed at WWDC, launching in the fall.
Apple TV May Gain Deeper Integration With iOS and Macs via Continuity
As noted by 9to5Mac, the notifications are being received on Macs running on the same local WiFi network as Apple TVs that also have the newest software, suggesting at the least, that with Yosemite, Macs will be able to interact with the Apple TV in new ways.
It is unclear how Yosemite and the Apple TV might interact as any Continuity features between the two are not yet functional, but it is possible that a feature like Handoff could be used in conjunction with AirPlay, allowing a movie, TV show, or music to be seamlessly transferred from one device to another.
It's also possible the Apple TV could display notifications when a phone call is incoming to an iPhone, much like the Mac and the iPad are able to do. Call notifications and on-screen caller ID are not far-fetched, as some telecommunications providers that offer TV, Internet, and phone access are able to display caller information on screen.
Continuity features like Handoff appear to require Bluetooth 4.0, a feature that is only available in the third-generation Apple TV. Yesterday's update was only available for third-generation Apple TVs, providing more evidence that the device is likely to gain some Continuity features.
OS X Yosemite, the new Apple TV software, and iOS 8 are all expected to be released to the public in the fall after an extended beta testing period. Apple is also said to be working on an upgraded Apple TV set top box with new capabilities, which could also take advantage of Continuity features.