Tooltip
The new tooltip appears whenever you hover over an editable area.
Jason G. Lemieux was kind enough to help position it and define it’s appearance.
If you don’t need it, you can disable it from the settings page.
Restyled buttons
This is also Jason’s doing. Aren’t they pretty? :)
Extendable JavaScript
The ability to define your own editable fields was present from the beginning. However, you weren’t able to extend the built-in field types, since they were defined in JavaScript.
Developers now have access to the FrontEndEditor JavaScript object which contains all the field type definitions, as well as additional data.