GCC is very close to the 30-year mark (0.9 released 22 March 1987). Linux turned 25 this past year; Firefox (the C++ parts, at least) is very close to 25, depe

GCC is very close to the 30-year mark (0.9 released 22 March 1987). Linux turned 25 this past year; Firefox (the C++ parts, at least) is very close to 25, depending on what code you want to count. Apache is 20ish years old. Even LLVM, which I think of as a relatively young project, is getting close to 15 years. Maybe (hopefully?) very little code survives from the initial versions, but they've all withstood the test of time. It's certainly pleasing to be able to sit down and write something from scratch or nearly from scratch. But it can be equally pleasing to extend a multi-million line codebase to do something new, or to enable the codebase as a whole to do something new/better.