Released around the transition period of macOS Mojave and Catalina (roughly 2018–2019), was a critical stability update for the "AST 2" platform.
Fixed specific bugs related to Location Services on initial boot for macOS Big Sur and improved stability for macOS Monterey. Apple Service Toolkit - 1.5.3 30
Apple Service Toolkit (AST) - 1.5.3 30 is a specific diagnostic software suite used by Apple Authorized Service Providers (AASPs) and technicians to verify hardware health and troubleshoot issues across various Apple devices. Released around the transition period of macOS Mojave