See this ACM article on it: http://m.cacm.acm.org/magazines/2016/7/204032-why-google-stores-billions-of-lines-of-code-in-a-single-repository/fulltext http://m.c

See this ACM article on it: http://m.cacm.acm.org/magazines/2016/7/204032-why-google-stores-billions-of-lines-of-code-in-a-single-repository/fulltext http://m.cacm.acm.org/magazines/2016/7/204032-why-google-sto... Lots of things aren't source files: test data, config files, build files, metadata, documentation, etc.