Ok. As a result of this, PKG-INFO that contains the "Classifiers" fields still has 1.0 as Metadata-Version. Consequently,
http://pypi.python.org/pypi/pkginfo fails to read extra metadata fields. If Tres is reading this, I had to do the following hack as a workaroud:
from pkginfo import Distribution
class PkgInfoFile(Distribution):
# Not all packages' PKG-INFO define the proper metadata
# For eg., modern-package-template uses the Classifiers field and yet
# uses 1.0 as the metadata version (Classifiers is only defined in 1.1)
metadata_version = '1.2' # not all PKG-INFO file have proper metadata version