On the lid appears the city’s mascot: Hesomaru, who was initially the main character in the belly button festival held in the city, before becoming the city’s mascot. Below it is a map of the island of Hokkaido with Furano in the center, thus suggesting the belly button in the center of the mascot’s nose, and the reason for the festival.
Translation of the text on the cover: へその町 - belly button city