// http://heycam.github.io/webidl/#idl-ByteString
declare type ByteString = string;

// http://heycam.github.io/webidl/#idl-USVString
declare type USVString = string;

// http://heycam.github.io/webidl/#idl-DOMString
declare type DOMString = string;

// see: https://fetch.spec.whatwg.org/#headersinit
declare type OpenEndedDictionary = Object;