Captures a screen or application window to a MediaStream, for recording or sharing over the network. This allows conferencing services to provide shared presentations in a conference, and allows remote control tools like Chrome Remote Desktop to provide an image of the controlled computer's screen to the controlling computer.
Docs: https://docs.google.com/document/d/1XEoy_zPYQsRvAt2O68m769mTMN8bT0xqvWQyfPfqLmQ/edit?usp=sharing