Servo was a PoC browser that did not need to become an actually usable browser by itself, but it served as a test bed for writing browser parts in Rust so they

Servo was a PoC browser that did not need to become an actually usable browser by itself, but it served as a test bed for writing browser parts in Rust so they could be used to replace bits of Firefox (Gecko). Now it seems they are pushing for Servo as a browser and goal by itself.