This extension works on top of the Google search results page. The basic idea is to eliminate the additional hop between clicking on a Google Search result item and loading the desired page. When you are not using this extension, you will see on the monitor tab (developer tools) that Google sends you to a "google.com/url" page and then to the website you requested.
Behind the scenes, there are two positive side effects: more privacy (avoiding a tracker, google.com/url) and a faster browsing experience (fewer requests to load a page).
Firefox: https://addons.mozilla.org/en-US/firefox/addon/stop-googlesearch-proxy/
Chrome: https://chrome.google.com/webstore/detail/stop-google-search-proxy/hdjjpkgknpghnfoekbehekdliiljmjld
Extension disabled, so there is the extra hop Google Search adds between clicking and fetching the expected website. The blue line on the network monitor tab (bottom) shows this request.
Extension enabled, no calls to google.com/url before loading the expected page =D