The Remote Playback API can be found here:
GitHub repository: https://github.com/w3c/remote-playback/
File an issue: https://github.com/w3c/remote-playback/issues/new
The Remote Playback API requires to communicate with a device over the network. Some behavior would require a real devices to be implemented. In order to keep these tests automated, only behaviors that can be run without user gesture or specific configurations are available here.