I have just installed the DuckDuckGo add-on in Firefox 11.0, running on XP SP 3.

I would like to add additional parameters to the query string. However, any changes I make are not reflected in the query string when doing a search.

I found the duckduckgo.xml file at C:\Documents and Settings\User Name\Application Data\Mozilla\Firefox\Profiles\Profile Name.default\searchplugins. I opened it up with Notepad++ and added the line for kl=uk-en:

<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/" xmlns:os="http://a9.com/-/spec/opensearch/1.1/">
<os:ShortName>DuckDuckGo</os:ShortName>
<os:Description>Search DuckDuckGo (SSL)</os:Description>
<os:InputEncoding>UTF-8</os:InputEncoding>
<os:Image width="16" height="16">data:image/x-icon;base64, -Removed to shorten-</os:Image>
<os:Url type="text/html" method="GET" template="https://duckduckgo.com/">
  <os:Param name="q" value="{searchTerms}"/>
  <os:Param name="kl" value="uk-en"/>
</os:Url>
</SearchPlugin>

However, the kl=uk-en parameter does not appear in the query string when searching (despite several Firefox restarts).