The phrase refers to the process of acquiring and installing the application package file for the Android Lollipop operating system. This typically involves obtaining the file from a source external to the official Google Play Store. For example, a user might seek this package file to install the operating system on an older device or emulator.
The primary benefit lies in the ability to install a specific version of the Android operating system on devices or platforms where it is not officially available. Historically, this method has been employed for development, testing, or to revive older hardware. The importance is tied to the control it provides users and developers over the software environment of their Android devices.