Apple is the primary contributor and maintainer of WebKit at this point since Google forked Blink off of it. There are consulting firms like Igalia that work o

Apple is the primary contributor and maintainer of WebKit at this point since Google forked Blink off of it. There are consulting firms like Igalia that work on all three engines, and they're funded mostly from big clients like Bloomberg and banks so developers there can use flexbox and CSS grid everywhere. Google sometimes works on WebKit as well if they want to try to improve compatibility of websites, but the project is mostly Apple employees now.