Documentation for method named assembled from the following types:

class Parameter

From Parameter

(Parameter) method named

Defined as:

method named(Parameter:D: --> Bool:D)

Returns True if it's a named parameter.

my Signature $sig = :(Str $x, Bool :$is-named);
say $sig.params[0].named;                          # OUTPUT: «False␤» 
say $sig.params[1].named;                          # OUTPUT: «True␤»