What significant innovation combined braking and shifting functions into a single unit mounted on the brake hood?

Answer

STI (Shimano Total Integration)

STI is the technology, famously spearheaded by Shimano, that merged the brake lever actuation and the indexing shifting mechanism into one ergonomic unit located on the brake hood.

What significant innovation combined braking and shifting functions into a single unit mounted on the brake hood?
inventiontechnologymechanismbicycleshifter