Back in 2014, Google killed Google TV and announced Android TV, and as a result, introduced ADT-1, the first developer kit specifically designed for Android TV. Since then ADT-2 was introduced in 2018 in an HDMI stick form factor, and now the company has announced the launch of Android TV on Android 10 together with ADT-3 devkit targetting Android TV app development for Android 10.
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The "developer kit" just looks like a standard TV box, although It's really tiny and comes with what looks like a voice remote control.
Google