Excellent.
Using this add-on, however, there is no highlight effect when the pointer is hovering over the address bar and the search box.

英語わからなくても勘でできましたよ

This is brilliant. A few more customization options would be nice to have, but it's very usable and fun even now. More finegrained control over saving (e.g. choosing a name instead of saving a new version all the time) would also be nice.