It's been pointed out that eg, gzip is not at all standard on all the unix systems out there. Rpm2cpio does part of the job, but it cannot extract metadata. Assuming that bunzip2 is a standard linux tool, or that the package uses gzip compression instead. Rpm may depend on a list of packages, but boolean OR is not supported. However, boolean OR can be emulated using virtual packages and provides.
Some people consider file dependancies a gross misfeature.
Copyright info is included in debian packages, but not in an easily extractable format. Supported by a version of this package format used at one time by SuSE Linux. Supported by a version of this package format used at one time by SuSE Linux. To be useful, you need to get a tag number assigned to your new piece of metadata, which implies modifying the rpm program. Copyright 1998-2000 by Joey Hess under the terms of the GNU GPL, either version 2 or at your option, any later version.