Search Everywhere 0.4.2.1-signed.1-signed
In short, the interesting bits are:
* cref=www.google.com%2Fcse%2Ftools%2Fmakecse: this is the Google page we visit, google.com/cse/tools/makecse. It is publicly available, and the parameters added to this URL are governed by the Google's privacy policies.
* The parameters are described in Google's CSE documentation at http://www.google.com/cse/docs/tools.html, with one addition (agent=...). These are listed below, and described at the URL just provided.
-- url=http://www.gnu.org/software/tar/manual/html_chapter/index.html (the web page you are searching from, since Google needs to scan the page for links in order to build the on-demand Custom Search Engine)
-- pattern=path (the type of url-munging)
-- autofilter=1 (whether or not to eliminate hyper-popular websites from the search results)
-- boostexact (you'll have to read the docs, description is too context-dependent for here)
-- agent=searcheverywhereV0.4.0 (NOTE: this is the special parameter I've added, to be friendly to Google -- it simply identifies the search as coming from a Search Everywhere toolbar, and contains no other information)