This branch is meant for development of preview-level APIs and features.
Google APIs are typically deployed as API services that are hosted under different DNS names. One API service may implement multiple APIs and multiple versions of the same API.
Google APIs use Protocol Buffers version 3 (proto3) as their Interface Definition Language (IDL) to define the API interface and the structure of the payload messages. The same interface definition is used for both REST and RPC versions of the API, which can be accessed over different wire protocols.