Short answers, pulled from the story.
The European badger is an omnivore whose primary food source is earthworms. Its diet also includes large insects such as beetles, caterpillars and wasp nests, cereals including wheat, oats and maize, windfall fruit, and small mammals such as rabbits, mice, voles and hedgehogs. An adult typically does not eat more than 0.5 kg of food per day.
European badgers typically weigh 7-13 kg in spring and 15-17 kg in autumn. The heaviest verified specimen weighed 27.2 kg, and unverified reports have suggested weights as high as 34 kg. If average weights are used, the species ranks as the second largest terrestrial mustelid, behind only the wolverine.
A sett is the underground burrow system constructed and occupied by European badgers. Passage systems run 35-81 m in length, with nesting chambers situated 5-10 m from the entrance and more than a metre below ground. A single sett can have anywhere from a few exits to fifty, and the same sett may be passed down through multiple badger families for decades.
Badgers are culled in England in an attempt to reduce bovine tuberculosis in cattle, as badgers are considered the primary reservoir of Mycobacterium bovis in the southwest of England, Wales and Ireland. Bovine TB was first detected in UK badgers in 1971. A scientific study covering 2013 to 2017 found a 36-55% reduction in bovine tuberculosis incidence in cattle in culled areas, though the practice remains widely disputed.
The Oxford English Dictionary states the word badger probably derives from badge plus the suffix -ard, referring to the white mark on the animal's forehead. This etymology may date to the early 16th century. The older English name brock comes from the Proto-Celtic word brokko, meaning grey.
The European badger appears across European folklore and fiction. In Irish mythology, badgers are shape-shifters connected to Tadg, king of Tara. Kenneth Grahame's The Wind in the Willows features Mr. Badger as a gruff but wise and loyal figure. Beatrix Potter introduced a villainous badger named Tommy Brock in her 1912 book The Tale of Mr. Tod. T. H. White's The Once and Future King transforms the young King Arthur into a badger by Merlin's magic.