Branching is very well supported in Subversion. There is a reason feature branches occupy a large part of the SVN Book. I would say feature branches were mains

Branching is very well supported in Subversion. There is a reason feature branches occupy a large part of the SVN Book. I would say feature branches were mainstream usage of CVS too, but SVN made it more popular because merging is more effortless. Github probably popularized it, because they put a web interface on it (which is great), but that can be said for a lot of things.