Who doesn't know stof? He is an active contributor to so many PHP Open-Source projects that I just can list them all here. He is one of the top 10 Symfony contributors and his first contribution dates as far back as 2010 when he fixed a typo!
Today, I'm very happy to announce that he accepted to take greater responsibilities in the Symfony Core Team by becoming of the mergers.
As of now, he has the power to merge pull requests for the following Symfony components and bridges: BrowserKit, Config, Console, DependencyInjection, DomCrawler, EventDispatcher, HttpFoundation, HttpKernel, Serializer, Stopwatch, DoctrineBridge, MonologBridge, and TwigBridge.