I checked the SB-600 manual. On page 50, "Wide Area AF-assist" is a "feature" not a "mode" of operation of the SB600. But on page 26, it is listed as one of the available "flash mode" settings for the SB-600. I was not referring to the settings on the camera body.
The line art on page 10, point 7, designates the Af illuinators. the manual says nowhere that they are IR (or visible red). I learned that from Stan, and that they are also (dimly) visible red.