missing-or-old-pkg_summary.txt
 lists some missing pkg_summary files or pkg_summary files that are 
 probably too old

missing-important-packages.txt
 lists some NetBSD packages that maybe should be there; initially based 
 on doc/STATUS (which is very out of date).  (I chose only NetBSD since 
 many missing and I think other repos may not be official or maintained. 
 I think the maintained repos for other operating systems are hosted 
 elsewhere.)

duplicate-package-names.txt
  lists PKGNAMEs that are re-used for different packages.
  For now this is just for
  /ftp/pub/pkgsrc/packages/NetBSD/amd64/5.1_HEAD/All/pkg_summary.gz

multiple-versions.txt
  list old version(s) of same package still provided by the repo.
  (same PKGPATH). (Why are these old packages still here? What will
  remove them?).
  This is also just for
  /ftp/pub/pkgsrc/packages/NetBSD/amd64/5.1_HEAD/All/pkg_summary.gz

old-package-repos.txt
  list package repos that are a few months or older

old-package-symlinks.txt
  lists symlinks to package repo versions that are a few months or older

old-pkg_summary-symlinks.txt
  lists some symlinks that lead to some old pkg_summary files
  that don't match up with packages hosted.

pkgin-wrong-repo.txt
  lists pkgin packages that have missing corresponding pkg_summary database;
  or has wrong arch or osrelease configured.

The other files show the removals or additions of packages found in few 
old pkg_summary files. (I need to remove the second pkg_summary 
differences if is redundant.) Note that I do not generate new
package summaries for all repos. And note I do not replace any
existing or install a new package summary. (What handles that?)

This will need some tuning. But hopefully it is useful.

I also plan to check if some important opsys/arch/version repo is 
missing and check if some packages are too old. And check if
the symlinks or directories are missing for real NetBSD releases
for common platforms (so pkgin can work without configuration).