Search with Gemini от Alexey Kudryavtsev

This tool lets you use the Google Gemini website as a search engine directly from your browser's URL/search bar.
When you use the configured search engine, the Gemini page will open with your query as the first message in a new chat.
The extension automatically registers "Gemini" as a new search engine in your browser with the keyword gem. You can customize the search keyword/shortcut in Firefox Settings/Search