I'm not familiar with all of them, but I know several of them are tools. Isn't it in apple's best interest to open source the tools if people use and improve them, and subsequently it means they get more money from the app store? And if these are the only things they open source, they still have a tight fist on the vast majority of their code base.
While on the subject of apple and FOSS. They may open source some tools, but do they give back to other projects? I.e. does apple push upstream? Substantially less than google and ms. And I would go so far to say almost never.