NetSurf is a free, open source web browser. It is written in C and released under the GNU Public Licence version 2. NetSurf has its own layout and rendering engine entirely written from scratch. It is small and capable of handling many of the web standards in use today.
Servo is a prototype web browser engine written in the Rust language. It is currently developed on 64bit OS X, 64bit Linux, Android, and Gonk (Firefox OS).