AU
Definition
Audio Units, Apple’s native audio plugin format for macOS. Used by Logic Pro as its sole plugin format, and supported alongside VST by Ableton Live and Reaper on Mac.
Context
AU plugins are exclusive to macOS. Logic Pro requires all third-party plugins to be in AU format. During the Apple Silicon transition, AU plugins needed to be recompiled for M1-native support, as Logic Pro did not support running under Rosetta.