Absolutely cute! Rated 5 out of 5 stars
People will ask "What version of Firefox is THAT?!" when you install this extension. Absolutely cute.
There is no Options interface, and the images vary slightly from what appears in the screenshots above. It would be great if the author added some options for customization; selecting which graphics to use, adding graphics, and allow random rotation of graphics each time a window (bookmarks, downloads, etc) is created and destroyed.
Pretty extension! Recommended if you have children or just appreciate japanese culture.