From the road.cc article on the Education Firsts Cannondale SystemSix, was this photo -
I was wondering about the purple part was and what difference it made to the gear change? It appears to a beefed-up replacement for both the standard RD hanger of the Cannondale frame and the first attachment section of the Shimano RD?
Wondering if they have found a lack of rigidity in those parts and want to get a more precise gear change by replacing with a single rigid linkage (with the associated downside of a crash now likely to break the frame given the sacrificial hanger is removed)? Any ideas?