The parser can run before the user is asked for permission to make changes. The parsed metadata can then discourage the user from installing the package (e.g. b

The parser can run before the user is asked for permission to make changes. The parsed metadata can then discourage the user from installing the package (e.g. because of extremely questionable dependencies). Dependencies are probably in the apt database and do not need parsing, but not everything is, or perhaps apt can install arbitrary .deb files now?