What does bonobo do???

Can anyone tell me what is the purpose of the bonobo directory in ggv (i have version 2.12.0 downloaded from the net). I have removed it from the make file as well as removed all the files from that directory and yet ggv works just as normally as before. If that is the case then how do the functions which control the cursor and key presses and other mouse events handled since these event handlers are present in the file ggv-postscript-view.c present in the bonobo directory.