packaging is part of pypa so is likely to see updates in a more timely fashion for new metadata versions.

PEP 794 support is still outstanding at this timepypa/packaging#945 but I'm not sure what the support path forpkginfo is for new metadata versions.

twine migrated over about a few months ago:pypa/twine#1180

There are no convenience methods for parsing bdist/sdist/wheel files like whatpkginfo provides, but maybe rolling our own implementation isn't too difficult?