David Singleton, Google’s engineering director for Android Wear, the company’s platform tailor-made for wearable devices, is sitting in Google’s headquarters here playing air guitar. As he strums his right hand in front of his Moto 360, the Motorola smartwatch set to hit the market this week, Singleton praises the third-party software developers using Wear. The company debuted the software in March, modified from Android, the most popular operating system in the world for smartphones and tablets. “There are a lot of apps out there,” he says after he stops strumming, during an interview here. As for the guitar-playing program: “We would have never thought of that.” He won’t say exactly how many apps there are, but offers that “thousands” of the more than 1 million programs in the Google Play store — where consumers download apps for their Android devices — have been updated to support Wear.