<literal>Valid-Until</literal> header, but if they don't or a
stricter value is desired the <literal>Max-ValidTime</literal>
option below can be used.
+ The <option>Check-Valid-Until</option> option of &sources-list; entries should be
+ preferred to disable the check selectively instead of using this global override.
</para></listitem>
</varlistentry>
the earlier date of the two is used as the expiration date.
The default value is <literal>0</literal> which stands for "valid forever".
Archive specific settings can be made by appending the label of the archive
- to the option name.
+ to the option name. Preferably, the same can be achieved for specific
+ &sources-list; entries by using the <option>Valid-Until-Max</option> option there.
</para></listitem>
</varlistentry>
frequently updated archive with a <literal>Valid-Until</literal> header
instead of completely disabling the expiration date checking.
Archive specific settings can and should be used by appending the label of
- the archive to the option name.
+ the archive to the option name. Preferably, the same can be achieved for specific
+ &sources-list; entries by using the <option>Valid-Until-Min</option> option there.
</para></listitem>
</varlistentry>
</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>
+
</variablelist>
</refsect1>