+
+ <varlistentry><term><option>Languages</option></term>
+ <listitem><para>The Languages subsection controls which <filename>Translation</filename> files are downloaded
+ and in which order APT tries to display the description-translations. APT will try to display the first
+ available description in the language which is listed first. Languages can be defined with their
+ short or long language codes. Note that not all archives provide <filename>Translation</filename>
+ files for every language - the long language codes are especially rare.</para>
+ <para>The default list includes "environment" and "en". "<literal>environment</literal>" has a special meaning here:
+ it will be replaced at runtime with the language codes extracted from the <literal>LC_MESSAGES</literal> environment variable.
+ It will also ensure that these codes are not included twice in the list. If <literal>LC_MESSAGES</literal>
+ is set to "C" only the <filename>Translation-en</filename> file (if available) will be used.
+ To force APT to use no Translation file use the setting <literal>Acquire::Languages=none</literal>. "<literal>none</literal>"
+ is another special meaning code which will stop the search for a suitable <filename>Translation</filename> file.
+ This tells APT to download these translations too, without actually
+ using them unless the environment specifies the languages. So the
+ following example configuration will result in the order "en, de" in an
+ English locale or "de, en" in a German one. Note that "fr" is
+ downloaded, but not used unless APT is used in a French locale (where
+ the order would be "fr, de, en").
+ <programlisting>Acquire::Languages { "environment"; "de"; "en"; "none"; "fr"; };</programlisting></para>
+ <para>Note: To prevent problems resulting from APT being executed in different environments
+ (e.g. by different users or by other programs) all Translation files which are found in
+ <filename>/var/lib/apt/lists/</filename> will be added to the end of the list
+ (after an implicit "<literal>none</literal>").</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry><term><option>ForceIPv4</option></term>
+ <listitem><para>
+ When downloading, force to use only the IPv4 protocol.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry><term><option>ForceIPv6</option></term>
+ <listitem><para>
+ When downloading, force to use only the IPv6 protocol.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry><term><option>MaxReleaseFileSize</option></term>
+ <listitem><para>
+ The maximum file size of Release/Release.gpg/InRelease files.
+ The default is 10MB.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry><term><option>EnableSrvRecords</option></term>
+ <listitem><para>
+ This option controls if apt will use the DNS SRV server record
+ as specified in RFC 2782 to select an alternative server to
+ connect to.
+ The default is "true".
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry><term><option>AllowInsecureRepositories</option></term>
+ <listitem><para>
+ Allow the update operation to load data files from
+ a repository without a trusted signature. If enabled this
+ option no data files will be loaded and the update
+ operation fails with a error for this source. The default
+ is false for backward compatibility. This will be changed
+ in the future.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry><term><option>AllowDowngradeToInsecureRepositories</option></term>
+ <listitem><para>
+ Allow that a repository that was previously gpg signed to become
+ unsigned durign a update operation. When there is no valid signature
+ of a perviously trusted repository apt will refuse the update. This
+ option can be used to override this protection. You almost certainly
+ never want to enable this. The default is false.
+
+ Note that apt will still consider packages from this source
+ untrusted and warn about them if you try to install
+ them.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry><term><option>Changelogs::URI</option> scope</term>
+ <listitem><para>
+ Acquiring changelogs can only be done if an URI is known from where to get them.
+ Preferable the Release file indicates this in a 'Changelogs' field. If this isn't
+ available the Label/Origin field of the Release file is used to check if a
+ <literal>Acquire::Changelogs::URI::Label::<replaceable>LABEL</replaceable></literal> or
+ <literal>Acquire::Changelogs::URI::Origin::<replaceable>ORIGIN</replaceable></literal> option
+ exists and if so this value is taken. The value in the Release file can be overridden
+ with <literal>Acquire::Changelogs::URI::Override::Label::<replaceable>LABEL</replaceable></literal>
+ or <literal>Acquire::Changelogs::URI::Override::Origin::<replaceable>ORIGIN</replaceable></literal>.
+
+ The value should be a normal URI to a text file, expect that package specific data is
+ replaced with the placeholder <literal>@CHANGEPATH@</literal>. The
+ value for it is: 1. if the package is from a component (e.g. <literal>main</literal>)
+ this is the first part otherwise it is omitted, 2. the first letter of source package name,
+ expect if the source package name starts with '<literal>lib</literal>' in which case it will
+ be the first four letters. 3. The complete source package name. 4. the complete name again and
+ 5. the source version.
+ The first (if present), second, third and fourth part are separated by a slash ('<literal>/</literal>')
+ and between the fourth and fifth part is an underscore ('<literal>_</literal>').
+
+ The special value '<literal>no</literal>' is available for this option indicating that
+ this source can't be used to acquire changelog files from. Another source will be tried
+ if available in this case.
+ </para></listitem>
+ </varlistentry>
+