The address bar in Firefox serves as our gateway to the internet, and by default, the browser tries to intelligently guess what we want based on our input. If it resembles a URL, Firefox makes the request; if not, it sends the string to the default search engine. Usually, this works fine, but there are times when we desire more control over the results. To achieve this, Firefox allows us to modify the search behavior with certain symbols. For example, using “*” before a search term will filter results from bookmarks, while “^” filters results from browsing history. By understanding these modifiers, users can refine their searches to specific areas of interest within Firefox.
https://wiki.tilde.institute/w/firefox-address-bar-tips