Shimano’s Light Action design involved mounting the cable clamp bolt on a short lever that was independantly sprung, allowing some ‘give’ before the parallelogram was shifted. It was the direct descendant of the ‘cable saver’ on the Shimano Lark and Eagle designs.
I liked it a lot. Combined with well made, affordable, slant parallelogram derailleurs it gave a slick, fluid shift - tangibly nicer than SunTour’s comparably priced offerings of the time.
This example is a (very) long pulley cage version of the workhorse of the Light Action range - with a steel outer parallelogram plate and a hanger plate that looks as though it is removable, but in fact is not (the allen bolt is not a standard 10mm fitting).
Browse associated documents.