I understand you're looking for a "solid paper" (likely a research paper, documentation, or firmware) related to in a downloadable ZIP format.

Android 7.1.2 is a minor update to the Android 7.1 (Nougat) operating system. It was released in April 2017 and offers several bug fixes, security patches, and performance improvements. Android 7.1.2 is compatible with a range of devices, including Nexus and Pixel devices.