The Android SDK isn't something that normal users see all that often (except perhaps when they're unlocking the bootloader on a new phone), but developers still rely on it heavily. One of the components included in the collection of desktop tools is Google's first-party Android emulator. It's a way of running a simplified version of Android software on a computer for the purpose of testing apps. And as cool as that sounds, it's also kind of a hassle - like all emulators, it's significantly slower than using Android on native hardware. But that's changing with the latest release, at least according to Google.