Un petit coup de main ?
scroogle-fr.xml
<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/" xmlns:os="http://a9.com/-/spec/opensearch/1.1/">
<os:ShortName>Scroogle fr</os:ShortName>
<os:Description>Scroogle French</os:Description>
<os:InputEncoding>UTF-8</os:InputEncoding>
<os:Image width="16" height="16">data:image/x-icon;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8%2F9hAAAACXBIWXMAAA3XAAAN1wFCKJt4AAAAKklEQVQ4jWNgGPKAkYGBgYGF6c9%2FdIkff7CoZuHAEGKi1AWjBowaMEwAACEBBBXMQ%2FVUAAAAAElFTkSuQmCC</os:Image>
<IconUpdateUrl>file://localhost/home/share/icons/fr.ico</IconUpdateUrl>
<SearchForm>http://www.scroogle.org/scrapfr8.html</SearchForm>
<os:Url type="text/html" method="POST" template="http://www.scroogle.org/cgi-bin/nbbw.cgi">
<os:Param name="Gw" value="{searchTerms}"/>
<os:Param name="l" value="fr"/>
<os:Param name="n" value="2"/>
</os:Url>
</SearchPlugin>
scroogle.xml
<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/" xmlns:os="http://a9.com/-/spec/opensearch/1.1/">
<os:ShortName>Scroogle</os:ShortName>
<os:Description>Scroogle Scraper (referrer safe)</os:Description>
<os:InputEncoding>UTF-8</os:InputEncoding>
<os:Image width="16" height="16">data:image/x-icon;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8%2F9hAAAACXBIWXMAAA3XAAAN1wFCKJt4AAAASUlEQVQ4je2RMQrAMAwDz0FD%2Fv9aDyLNA9rQgIcM7S0ehA%2BB4DSh5msVJv1VIIA0dN0vzj3B4zOAPtGgvEJ4rAU7hJuKgr9BmQk5kTgNvrCpmAAAAABJRU5ErkJggg%3D%3D</os:Image>
<IconUpdateUrl>file://localhost/home/share/icons/us.ico</IconUpdateUrl>
<SearchForm>http://www.scroogle.org/cgi-bin/scraper.htm</SearchForm>
<os:Url type="text/html" method="POST" template="http://www.scroogle.org/cgi-bin/nbbw.cgi">
<os:Param name="Gw" value="{searchTerms}"/>
<os:Param name="n" value="2"/>
</os:Url>
</SearchPlugin>
à placer sous /usr/lib/firefox-addons/searchplugins/xx-YY/ (xx-YY selon la langue utilisée)