QtCore.pyi has this type stub for QCoreApplication:

class QCoreApplication(PySide6.QtCore.QObject):
    }}{{# ...
    @staticmethod
    def translate(context: bytes, key: bytes, disambiguation: Optional[bytes] = ..., n: int = ...) -> str: ...

Actually passing a bytes argument causes a runtime error, while passing in a str is rejected by the type checker, but works fine at runtime.

The same issue apparently already existed for QObject: https://bugreports.qt.io/browse/PYSIDE-1329

Expected is to have the arguments properly declared as str in the type stubs.