<listitem><para><literal>Missing</literal> is the number of package names that were referenced in
a dependency but were not provided by any package. Missing packages may
- be in evidence if a full distribution is not accessed, or if a package
+ be an evidence if a full distribution is not accessed, or if a package
(real or virtual) has been dropped from the distribution. Usually they
are referenced from Conflicts or Breaks statements.</para>
</listitem>
</varlistentry>
<varlistentry><term>pkgnames <replaceable>[ prefix ]</replaceable></term>
- <listitem><para>This command prints the name of each package in the system. The optional
+ <listitem><para>This command prints the name of each package APT knows. The optional
argument is a prefix match to filter the name list. The output is suitable
for use in a shell tab complete function and the output is generated
extremely quickly. This command is best used with the
- <option>--generate</option> option.</para></listitem>
+ <option>--generate</option> option.</para>
+ <para>Note that a package which APT knows of is not necessarily available to download,
+ installable or installed, e.g. virtual packages are also listed in the generated list.
+ </para></listitem>
</varlistentry>
<varlistentry><term>dotty <replaceable>pkg(s)</replaceable></term>