What does gnome-pkgview do?

gnome-pkgview does two things to help decide what version of GNOME you are running. Depending on who you ask there are two differing views on this:

There is no specific GNOME version. pkgview displays the versions of desktop components installed via their pkg-config .pc files. It also gives the prefix (to determine between multiple versions) and a description.
Use gnome-version.xml, dammit! pkgview displays the desktop version and vendor string as per this file. You can even replace pixmaps/logo.png with your company's own expensive focus-group targetted corporate image! I've recently heard that Debian packages don't always include this file in gnome-desktop. Hassle your local Debian packager.

Things gnome-pkgview doesn't do:

deal with several installed GNOME versions very sensibly. Firstly, I don't have the resources or time to have more than one version. Secondly, this tool is really to enable end-users to report useful information to admins/gurus. Having extra complexity would just be bad. Hopefully, gnome-pkgview does the right thing with the details of the version its currently running under.
tell you what updates are available at ftp ftp.gnome.org Nice idea. Also worrying feature creep. This isn't red-carpet. Maybe one day gnome-pkgview will advise people of recent updates to what they're running.

Debian packager advice - name was too general. Also discovered an ancient RPM front-end called that.