Short answers, pulled from the story.
The Gaulish name Bituriges Cubi translates to kings of the world or possibly perpetual kings. This meaning derives from the stem bitu- which means world or perhaps eternal and the second part riges refers to kings in the singular form rix.
Their chief town during the pre-Roman era was Avaricum Biturigum and modern Bourges occupies that exact location today. They dwelled west of the Aedui people south of the Carnutes and Cenomani tribes with lands extending north of the Pictones and Lemovices groups.
Julius Caesar mentioned them simply as Bituriges in the mid-first century BC. Strabo wrote Bitoúriges oi Kouboi in the early first century AD while Pliny described them as Bituriges who are called Cubi during his lifetime.
Their chief town Avaricum fell in 52 BC after Roman attacks but this was the only oppidum spared by Vercingetorix scorched-earth tactics. Rome suppressed a Gallic revolt in their territory in 51 BC and submission to Rome happened quickly according to historical accounts.
The region later became known as Berry attested in 860 as pagus Biturigus and the name derives directly from the ancient tribe name. Historical records show city names evolved through forms like civitas Biturigum around 400 AD and later documents record Bituricas in 844 and Bituris in 1182.