It doesn't look like the file `MANIFEST.in' was supposed to be installed. $ bzcat /usr/share/doc/pybugz-0.9.0_rc2/MANIFEST.in.bz2 include LICENSE include contrib/*
MANIFEST.in should not have been in the tarball to begin with. This has been fixed upstream and will not be there for the next release.
I am reopening this, because after looking into it further, I found out that distutils.eclass installs this file by default if it exists in a tarball.
This bug was originally filed against www-client/pybugz-0.9.0-rc2 because it installed MANIFEST.in in its doc directory. I initially removed that file from the generated tarball upstream. However, I have since discovered that this file is automatically installed by distutils.eclass, and I tend to agree with the original description of this bug. This file is used in the generation of the tarball for a distutils package, but I can't think of a good reason to install it in the documentation for the package.
I suggest to also disable installation of PKG-INFO.
distutils_src_install() no longer installs MANIFEST* and PKG-INFO.