HTML5 adds support for some specialized input types, some of which Firefox supports. Types like "email", "tel" and "url" not only trigger form data validation, they also enable special keyboards on mobile devices making it easier to enter data.
As pages are loaded, the add-on will scan the DOM for input elements. If the element does not already use a specialized HTML5 type and element appears to collect email, telephone or URL text, the add-on will add the appropriate "type" attribute to the element. The add-on guesses the type of input based on a simple regex that is matched against the ID, name and class of the element.