Promise.all: Order of resolved values

Looking at MDN it looks like the values passed to the then() callback of Promise.all contains the values in the order of the promises. For example:

var somePromises = [1, 2, 3, 4, 5].map(Promise.resolve);
return Promise.all(somePromises).then(function(results) {
  console.log(results) //  is [1, 2, 3, 4, 5] the guaranteed result?
});

Can anybody quote a spec stating in which order values should be in?

PS: Running code like that showed that this seems to be true although that is of course no proof – it could have been coincidence.