Bernhard Kau

Kau-Boy’s OpenSearch is deprecated and will be removed from the plugin directory on July 29, 2023, 13 years after its first release. If you still want to use OpenSearch on your site, I recommend switching to <a href="https://de.wordpress.org/plugins/open-search-document/" rel="nofollow ugc">Open Search Document</a> which is still actively supported.
Integrates an OpenSearchDescription so that users can add your blog as a search location to their browsers. Your favicon will also be visible next to the search option in the browser.
You don’t need to setup any information. Just install and activate the plugin!

Kau-Boy's Opensearch

Integrates an OpenSearchDescription so that users can add your blog as a search location to their browsers. Your favicon will also be visible next to  …

Jeff Waugh

Add OpenSearch discovery and querying to your WordPress site, based on the 
<a href="http://www.opensearch.org/Home" rel="nofollow ugc">OpenSearch</a> specification, version 1.1.
After activating the plugin, your WordPress site will expose a standardised 
search interface, accessible to OpenSearch clients such as the <a href="http://www.mozilla.com/firefox/search.html" rel="nofollow ugc">Firefox 
search bar</a>.

OpenSearch

Add OpenSearch discovery and querying to your WordPress site.

Kau-Boy's Opensearch vs OpenSearch