Mozilla Alive
Netscape's open-sourced heir — the project (1998), the Foundation (2003), Firefox, and Rust. The only major browser engine not owned by a platform monopoly for a crucial decade.
Netscape open-sourced Navigator as 'Mozilla' (its internal codename — Mosaic-killer-Gozilla) on March 31, 1998. The rewrite took four years and produced Firefox (2004), which broke IE's monopoly and reopened the web.
The Mozilla Foundation (2003) and its taxable subsidiary fund development through search deals. Rust (2010, Graydon Hoare), Servo, and MDN are its other exports; it remains the independent check on browser hegemony.