Jeff ?, code name Bronco, is an Exemplar-3 and PK-3. He's not too bright -- he's still a sophomore at age 17 from having been held back. He and his buddy Silo think it's the height of humor to look at something, ask "what's this?" and watch it break. They're on permanent detention with Maintenance and Repairs to fix what they've broken. Jeff is said to resemble a young Fred Ward.