It's not exactly clear to me why they hired Nikita Popov, but I'm glad he gets such free rein. I was involved with PHP runtime development in the beginning of the 2010s and saw as he, as a teenager in high-school, progressed so quickly from fixing some bugs to being arguably the person most advancing the language and the implementation (the other being Zeev, who's been around forever, but he's more focused on the implementation).