I just went through this trying to undo the yahoo search engine that the pdfforge toolbar installs.
Easiest way is probably to install Firebug (useful for so many things), and do the following:
- go to about:home
- open the Firebug Console tab
type in (all on one line, shown here for clarity):
name property is the search engine name, and
searchUrl is the appropriate URL, with the magic token
_searchTerms_ being replaced by the keywords you type into the Firefox search box.
Then reload about:home and try again.
I got to this answer by looking at the source HTML code for the about:home page, which loads chrome://browser/content/aboutHome.js that contains code to access
localStorage['search-engine'] and use it to update the
window.location.href based on the
searchUrl and what you type into the search box.