Hello Paul,

Please take a look at this :

https://www.reddit.com/r/firefox/comments/gw74vx/twitter_missing_from_search_bar/

Also see :

https://www.reddit.com/r/firefox/comments/fvfs0i/twitter_search_engine_disappears_after_update/

Two additions to the above:

(1) Apparently there was an agreement between Mozilla and Twitter to bundle the Twitter search engine into the product for some period of time and that has ended, so it's now only available to be added on.

(2) I couldn't find an add-on on the Add-ons site, so I created a new one and it is currently being reviewed. The code and a link to the expected future location can be found here:

https://github.com/jscher2000/twitter-search-extension

Update -- approved and available here:

https://addons.mozilla.org/firefox/addon/twitter-search/

I thought it must be something like an agreement ending. Sigh :{

Thanks for feedback all.