I just have duckduckgo as my default search engine, that way I can use the bangs to search almost any site that's even remotely mainstream by starting my search with !w (wikipedia), !y (youtube) !hn (hacker news), !g (google), etc.

There is related functionality built-in to Firefox (since basically forever) you can assign keywords to any installed search provider and then search that specific search engine by prefixing your search with the keyword you assigned. So you could assign !g directly in Firefox options and Firefox will take you directly to Google for that search (no need for the intermediate duckduckgo).

You can add things like YouTube etc as well so long as they have "OpenSearch" metadata. (Presumably what Chrome is using for "tab to search"?) [1]

[1] https://support.mozilla.org/en-US/kb/add-or-remove-search-en...

Firefox is getting rid of, or has already got rid off, OpenSearch integrations[1].

What you're describing is a bookmark substitution search feature that's independent of OpenSearch, and Mozilla calls the feature keyword searches[2].

[1] https://en.wikipedia.org/wiki/OpenSearch#Support

[2] http://kb.mozillazine.org/Using_keyword_searches

My understanding is that Firefox still uses the OpenSearch metadata shallowly as the easiest way to create the "keyword search bookmarks" rather than writing a bookmark by hand (though your second link was what I was looking for on how to do that and it seems quite easy/convenient to do yourself if you had to). I don't believe that shallow auto-bookmark discovery is/will be dropped, they dropped a more complicated add-on/extension-based approach that supported more OpenSearch features.

Thanks for taking the time to explain the change, it looks like you're correct.