YoctoPlay is an app for your Apple TV which offers a Home Screen shortcut to a single YouTube video.
This website component receives the desired video URL.
A secret number is used so this website knows which Apple TV's copy of YoctoPlay is to receive the desired YouTube video.
Once the video has been successfully relayed to your Apple TV's YoctoPlay app, the app stops checking this website. The video shortcut can not be dynamically updated on YoctoPlay's end.
YoctoPlay app permanently remembers a single video URL, and that video can not be changed within the app. (Otherwise watching a video could not be a single-click experience.)
To change YoctoPlay video shortcut, you would need to delete YoctoPlay off your Apple TV's Home Screen, and then reinstall it from Apple TV's App Store.
Each individual Apple TV running YoctoPlay must be programmed with its own video. No videos are shared across your Apple accounts, or iCloud accounts.
YoctoPlay does require YouTube app also be installed on your Apple TV. It can function with YouTube either logged into an account, or not.
Privacy: The only information recorded on YoctoPlay server is user IP address. This is to combat against nefarious actors trying to guess secret numbers. There is no "user account" of any kind. YoctoPlay does not know your name, your email, nor your Apple ID.
Contact: [email protected]