CAF (Core Audio Format) is a sophisticated audio container developed by Apple to overcome the 4GB file size limit of older formats like AIFF and WAV. It is designed to support high-resolution audio, multi-channel surround sound, and widely varying data formats. CAF is the native format for many audio applications on macOS and iOS. Sample CAF files are used to test advanced audio features in the Apple ecosystem. Developers use them to verify support for 64-bit file offsets (allowing for massive recordings) and to test the handling of complex channel layouts. They are also used to test the efficiency of background audio recording on mobile devices.