Android Go extends and continues past efforts to reduce resource usage.

MOUNTAIN VIEW, Calif.—Starting with Android 4.4, Google began to support a "low RAM" flag for devices with 512MB of memory. The low-RAM configuration changes how the OS and supported apps work, with the goal of reducing resource usage. That initiative was called "Project Svelte," and it was aimed at low-end phones for emerging markets. Today at Google I/O, the company announced a new initiative to continue and extend these efforts. "Android Go" will be a part of Android O, and it will also include optimized versions of apps and the Google Play Store to reduce resource and data usage.

Think of Android Go as a modified version of Android O. Controls to keep an eye on and control data usage have been added to the quick settings, while the existing Data Saver feature in Chrome will be enabled by default. Some apps have also been rethought for connections with low bandwidth or low data caps. YouTube Go, for instance, will let you see a preview of a video before you download the whole thing. It will also allow you to save videos for offline use and peer-to-peer sharing so you can save your friends and family some data, too.
Apps that have been optimized for Android Go devices will be highlighted in the Google Play Store, though the Store will also offer the full library of Android apps available for regular phones. Google has published a new page called "Building for Billions" that will aid developers in optimizing their apps for lower-end phones with smaller, lower-resolutions screens and poor data connections.

All Android devices with 1GB or less of RAM will automatically use the "Go" configuration of Android, and all Android releases going forward will have "Go" configurations for these low-end devices. The feature will come to market with the regular version of Android O, which is currently in beta and will be available this fall.