No, it is unrelated to the Google search-bar or toolbar.
1. In the Firefox URL/address bar type in about:config
and press Enter
2. Firefox will then greet you with a warning in the browser section, click the "I'll be careful, I promise" button to proceed. -- That is when the Filter box will appear just below the other toolboxes at the top.
3. Type in keyword
in the filter box.
4. Amound the various results in the browser section will be keyword.URL
-- Double click that and when you do, a box will pop-up.
5. Enter the string that Sawg suggested in the pop-up box...
and Press OK
6. You then can get out of the editing mode by pressing the back button or typing in a address in the URL/address bar.