Is OpenSearch Auto-Update Still Supported in Firefox?

Firefox Development
1 
<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/">
   ...
   <Url type="application/opensearchdescription+xml" rel="self"
       template="https://example.com/opensearch.xml" />
</OpenSearchDescription>

Does Firefox still support automatically updating the opensearch XML description?
MDN still mentions this feature: OpenSearch description format - XML | MDN

Also, in about:config, there used to be an “browser.search.update.interval” entry that specified the update interval. I can’t find it anymore.