élastique
Berlin-based zplane's licensed time-stretching and pitch-shifting engine — the thing actually doing the work when you drag an audio clip in many DAWs.
Few DAW makers write their own time-stretching. It is hard to do well, and zplane.development has made a business of selling exactly that piece. élastique comes in several modes: Pro for top quality, Efficient for low CPU and Soloist for monophonic sources such as vocals, where formants can be preserved so that a voice doesn't turn into a chipmunk after pitch shifting.
The engine appears by name in the menus of REAPER, Cubase and FL Studio, and anonymously in many more. A textbook example of a component most users have heard without ever having heard of.