> You can use more than one autocomplete value at a time too. If your username is also an email address you can give the browser and any associated password managers a hint with ‘autocomplete="username email"’.

This whole paragraph is incorrect. While the attribute value does allow multiple tokens there is a very specific syntax defined in the HTML standard and it doesn’t support multiple field names (types) i.e. autocomplete="username email" is invalid. If you access ‘input.autocomplete’ on an input with that attribute value “” will be returned indicating this.