I'm curious about the matching for the Maybe type (type Maybe<T> = T | void;). Is void an alias or superset of undefined? Perhaps because undefined is a reserve

I'm curious about the matching for the Maybe type (type Maybe<T> = T | void;). Is void an alias or superset of undefined? Perhaps because undefined is a reserved word? Wouldn't it make more sense if it was either: type Maybe<T> = T | undefined; x === undefined Or: type Maybe<T> = T | void; x === void; // or: void?(x)