A graphing calculator
In 2012, Google discontinued its highly-regarded code search. It was freely available for open source projects residing on Google Code project hosting. This is the only description of the pre-2012 Google Code Search I could find:
…it was designed to help people search for open source code all over the web [and] will be shut down along with the Code Search API on January 15, 2012.
Simultaneously, a graphing calculator functionality was introduced to regular search.