As a follow up to https://bugzilla.mozilla.org/show_bug.cgi?id=1542243

So wikipedia has 128 matches in https://searchfox.org/mozilla-central/source/browser/components/search/extensions/list.json, I believe its available in every locale configuration and in the vast majority of cases the locale of the engine matches the users locale

One of the side benefits to switching to WebExtensions for search engines is that we may be able to use the WebExtensions to handle the localisation of engines instead of us doing so manually in SearchService. We need to do that on an opt in case by case basis and it seems like wikipedia might be a good first choice

I think we could do something like

{
  "engineName": "wikipedia",
  "webExtensionId": "wikipedia@search.mozilla.org",
  "appliesTo": [{ 
    "included": { "everywhere": true " },
    "webExtensionLocale": "$USER_LOCALE"
  }]
},

And have webextensions install the engine matching the users locale instead of listing wikipedia 128 times

https://hg.mozilla.org/mozilla-central/rev/19b8d6a399f6

https://hg.mozilla.org/releases/mozilla-beta/rev/19b8d6a399f6