menu option system update

[StoneRyno]

Today I had to call sprint because of a technical issue involving voicemail. In the process the rep asked me to go to the homescreen, then press the menu button, and choose system update. Was told it may also be in the about phone section. Even though I am using CM7 I figured everything settings would be there. To be surprised it was not. So I told them perhaps something went wrong when I updated and if needed I could download the stuff to do the update all over again completely resetting back to out of box. Anyways we were able to solve it without the need to access that menu item. But I'm curious as to what that menu item contains and why it isn't present on CM7 and I'm going to assume possibly all/other custom ROMs.