Android is an open source operating system for mobile devices and a corresponding open source project led by Google.
The Android Open Source Project (AOSP) repository offers the information and source code needed to create custom variants of the Android OS, port devices and accessories to the Android platform, and ensure devices meet the compatibility requirements that keep the Android ecosystem a healthy and stable environment for millions of users.
Anyone is free to contribute code and fixes to the AOSP project repository, but Google oversees its general direction and the bulk of development. The AOSP regularly incorporates the latest bug and security patches for Android.
Google makes the AOSP available to users under the Apache 2.0 Software License. This means the AOSP is free to use and alter, but users are required to generate notice files any time they make additions to the underlying code. Each library has a legal notice for distributing that library.
AOSP generated NOTICE.html file is sometimes missing details resulting in being insufficient for license compliance. AOSP has an enormous amount of code. So it takes developers days and constant attention to this manual process . Historically, there hasn't been any way to automate this process, so companies have been forced to do this manually or risk not meeting their compliance obligations.
For many licenses, a valid interpretation is that it's insufficient to include a copy of the license, and that you need to reproduce every variant (e.g. with different copyright statements) of the license that's present in the source code.
When Google distributes AOSP, an individual library licensed under GPL will likely contain a NOTICE file with a (single) representative sample of the GPL license text. According to a lot of our customers' lawyers, however, the comments at the top of each source code file which indicate a copyright and reference GPL count as an abbreviated form of a license, therefore requiring them (the comments, not the full source files) to be included in the NOTICE file.