ansible/ansible — pull request #9436 by bobobox (2014-10-28 15:15:46+00:00)
Title: vars_files haven't been discussed yet

I think this is a chapter ordering thing... vars_files have not actually be explained yet (aside from a reference to them in the note right above, which also might need reconsidering?). I believe they do get introduced in the next section, 'Variables'.