[Pharo-project] why RefactoringEnvironment requires AST-Core

Hi lukas we would like to reuse the BrowserEnvironment for an experiment and I saw package: 'Refactoring-Environment' with: [ spec requires: 'AST-Core' ]; package: 'Refactoring-Tests-Environment' with: [ spec requires: 'Refactoring-Environment' ]; Do you know if this is correct? And why? Stef