It's the stock Android 4.2 keyboard, but it only requires Android 4.0. That means more users can try Google's keyboard (not just Nexus users) and the keyboard will improve faster, detached from the operating system updates. Google's stock keyboard has been uploaded to Google Play by third-party developers, but this time it's the official version and more people will install it.
"Google Keyboard has Gesture Typing (which lets you glide through letters to form a word, just lift your finger to enter a space), automatic error correction, and word predictions. You can also tap the microphone to compose messages with Voice Typing when you’re on-the-go. Together with dictionaries for 26 languages (plus keyboard layouts for a dozen more), it provides a fast, accurate, and reliable typing experience," informs Google.
For now, the app is restricted to a few countries, so you may see this message: "This item cannot be installed in your device's country". Google says it's initially available for "English-speaking locales but they'll be adding more countries soon". Android Police has download links for the APK file, so you can bypass the restrictions.