URLs typed in Firefox‘s location bar are by default automatically filled. This feature can be turned off if needed.
To do this :
First, access the Firefox configuration editor by typing the following in location bar :
about:config
Click on I accept the risk! to bring up the configuration editor.
Next, search for autofill parameter. Double click on browser.urlbar.autoFill so that it changes from true to false.
From now on, typed URLs won’t be auto filled.
Happy browsing.