Huh? If I have a resource I serve without Access-Control-Allow-Origin headers, all three browser engines won't make it available in cross-origin contexts. [1]
For example, here are a pair of pages which make a cross-origin fetch for a resource that either does (yes-cors) or does not (no-cors) opt into cross-origin resource sharing. In all three browsers yes-cors displays the contents of the resource, and no-cors (correctly) displays "error".
