def get_empty_kwargs(self) -> t.Mapping[str, t.Any]:
        """
        Provides kwargs for instantiating empty copy with empty()

        Use this method to provide custom keyword arguments to the subclass of
        ``Rule`` when calling ``some_rule.empty()``.  Helpful when the subclass
        has custom keyword arguments that are needed at instantiation.

        Must return a ``dict`` that will be provided as kwargs to the new
        instance of ``Rule``, following the initial ``self.rule`` value which
        is always provided as the first, required positional argument.
        """
        defaults = None
        if self.defaults:
            defaults = dict(self.defaults)
        return dict(
            defaults=defaults,
            subdomain=self.subdomain,
            methods=self.methods,
            build_only=self.build_only,
            endpoint=self.endpoint,
            strict_slashes=self.strict_slashes,
            redirect_to=self.redirect_to,
            alias=self.alias,
            host=self.host,
        )

        Provides kwargs for instantiating empty copy with empty()

        Use this method to provide custom keyword arguments to the subclass of
        ``Rule`` when calling ``some_rule.empty()``.  Helpful when the subclass
        has custom keyword arguments that are needed at instantiation.

        Must return a ``dict`` that will be provided as kwargs to the new
        instance of ``Rule``, following the initial ``self.rule`` value which
        is always provided as the first, required positional argument.
        
src/werkzeug/routing/rules.py