Quantum is now also a bit of an umbrella project for initiatives making Firefox faster. "Quantum Flow", for example, is an engine-wide effort to push performance in the bits that still C++.
Right. Servo is an engine that will be embeddable into apps that need to render HTML, not just browsers.
Ah, so like the omni-present webkit view?
Servo is the experimental browser (engine?)?
Quantum is the project that ports parts of Servo to Firefox over time?