So to clarify the state of frame rate matching using Netflix (with a few assumptions - feel free to correct)…
* Boxes like Roku, Nvidia Shield, and Apple TV can / do (?) provide the ability within their video playback API for app developers to flag when a video goes full screen, or is a trailer etc (and therefore the box knows when to change refresh rate), but only Apple got (or paid?) Netflix to actually implement a version of Netflix to do this a few years ago
* This version is now branched from the main branch / parent Netflix code, and Netflix no longer supports that feature going forward:
"Netflix did it in the Netflix app on apple TV and that app is from a few year old branch of Netflix. Netflix no longer supports the feature on the later branches of their app. If you want Netflix to add support for it back, the best place to give that feedback is to Netflix.
* Also going forward, Netflix will not certify any box that attempts auto frame rate matching at a system level (which is what Apple TV currently does AFAIK
* Meanwhile, Roku users complained to Roku / Netflix about black screens during trailers, and seeing as they run the parent Netflix code which doesn't recognise full screen or trailers (and Netflix don't want to support / give out that branched version anymore), Roku's solution was to kill off auto frame rate matching for Netflix completely:
* Like Roku, Nvidia also use the parent Netflix code, and rather than kill off frame rate matching, their solution is to keep frame rate matching for Netflix, but make it manual, and have the user dictate when to switch the frame rate (and therefore getting around the "auto frame rate matching at a system level" restriction)
* So Netflix currently continue to keep the branched version updated for Apple TV, but will eventually want to kill / grandfather that branch (if / when the Apple TV4k is superceded (?), unless Apple continue or start paying Netflix to keep that feature alive?), leaving it up to the device manufacturer to deal with it (ala the Shield and Roku)?