Not entirely sure what it was called, but I'm very curious. A friend of mine had a '73 (roughly) Peugeot, likely a UO-8 with a front der. I'd never seen before. Instead of a swing-arm pulled by a cable to move to derailleur, the cable moves a rod connected to the inner cage plate in or out of a box on the seattube clamp. What was the idea behind this?