Doug Gregor, the author of this proposal, is the chair of the modules study group of the C++ standards committee (source: http://www.open-std.org/jtc1/sc22/wg21

Doug Gregor, the author of this proposal, is the chair of the modules study group of the C++ standards committee (source: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3380.pdf http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n338...). And this proposal looks very similar to the C++ modules proposal by Daveed Vandevoorde http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3347.pdf http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n334... So it looks like Apple is working towards making this a standard, not a non-standard extension.