I was in duckduckgo and wanted to add a search engine field to my browser,
Usually you had to search the browser utility, but I was surprised when I saw that the browser was already detecting it.

How can I automatically find my site search?
Note:
I'm not looking (now) to implement an automatic suggestion function, I'm just trying to get a service stored in a browser (exactly the same behavior with stackoverflow + firefox)
-Edit -
I tried the code that I found on my site that matches the opensearch documentation:
1)
<link title="your service name" type="application/opensearchdescription + xml " rel="
search " href="/opensearch.xml ">
2) xml file: /opensearch.xml
<OpenSearchDescription>
<ShortName>DuckDuckGo</ShortName>
<Description>Search DuckDuckGo (SSL)</Description>
<InputEncoding>UTF-8</InputEncoding>
<LongName>DuckDuckGo Search (SSL)</LongName>
<Image width="16" height="16">http://duckduckgo.com/favicon.ico</Image>
<Url type="text/html" method="get" template="https://duckduckgo.com/?q={searchTerms}"/>
</OpenSearchDescription>
But with my domain name and URL, and firefox does not detect the service (same as in the picture), what am I missing?