Former Mozilla intern here. I started contributing to the codebase since a few weeks ago. There are good bugs to find and I can tell you from person experience

Former Mozilla intern here. I started contributing to the codebase since a few weeks ago. There are good bugs to find and I can tell you from person experience that contributing to large open source project like Firefox is satisfying. Though contribution is no brainier: it's difficult because there are things you can't understand. A lot of classes are not documented and you literally have to read multiple files to just grasp 1% of what that class does... hopefully we can do better on that part. But IRC is useful most of the time (to get a quick answer), espeically #security, #mozwebqa and #extensions. I am still waiting for review and landing my patch... If you want to do some testing not direct firefox development, consider #mozwebqa.