Annotated Reference Manual
Each chapter of the ARM handles a part of the Compose* language. In each chapter there is first an abstract of what that particular part of the language should do. After that the syntax and the semantics are demonstrated. How it can be used is shown in the examples. After that the legality rules and the FAQ are stated.
The how, what, and the design decisions are mentioned in the comments. If added there can also be specific platform comments for each Compose* platform.
When there is more to read about a chapter then this is mentioned in the “further reading” section of a chapter.