That's not what I think is going on here. He's not asking "Tell me the commands that I have to type to do X, Y and Z in GIT, SVN and Mercurial", he's asking a h

That's not what I think is going on here. He's not asking "Tell me the commands that I have to type to do X, Y and Z in GIT, SVN and Mercurial", he's asking a higher level question about how one can utilise VCS (and DCVS) tools to work in different ways. Depending on the experience of the candidates he's trying to acquire/interview, this may be appropriate to indicate that they have either experienced different ways of developing at different companies, or have an interest in software development practices wider than just "The way I've done it is the way I was told." I'd consider it an 'indicator' question, indicating that the candidate has either experience or interest in software delivery and the way that different organisations work/operate. It's probably not a make-or-break question, but if a candidate had a good number of years under his belt and hasn't at least heard of some kinds of different practices then they might be the "do what I'm told but no more" coder that that organisation wants to avoid.