I'm not sure if this should be fixed in the code or in the documentation, but the pkgutil.iter_importers() documentation says that pkgutil.iter_importers(name) should yield the "importers for sys.meta_path, sys.path, and Python’s “classic” import machinery, in that order" when name does not include a ".":

http://docs.python.org/dev/library/pkgutil.html#pkgutil.iter_importers

However, the function appends a "non-classic" pkgutil.ImpImporter at the end of all that:

Python 3.3.0b1 (default:5d43154d68a8, Jul  8 2012, 13:54:45) 
[GCC 4.2.1 Compatible Apple Clang 3.1 (tags/Apple/clang-318.0.58)] on darwin
>>> from pkgutil import iter_importers
>>> list(iter_importers())[-1]
<pkgutil.ImpImporter object at 0x1035fa840>

AFAICT, the intent of this function was to help provide a fully PEP-302 compliant import process wrapping the builtin C-implemented import mechanism. Nowadays, I believe that iterating over sys.meta_path should probably be enough.

Marking this a documentation issue because the same behavior is also present in 2.7:

Python 2.7.3 (default, Apr 19 2012, 00:55:09) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
>>> from pkgutil import iter_importers
>>> list(iter_importers())[-1]
<pkgutil.ImpImporter instance at 0x10517b710>

Closing as this is no longer an issue after Nick's pkgutil changes documented in issue 15343.