As I write this, the builders are compiling code without nsILocalFile for the first time. It's no longer used by any interface or C++ code - except for a few places where it's necessary to avoid everything blowing up. This should make working with files simpler and less confusing for new people, such as first-time add-on developers.
Using nsILocalFile from javascript code still works, and I haven't yet removed the JS uses of it from the tree.
