George,I'm not positive, but I think the gov.txt file was created with Spiderbomb. I know that Spiderbomb creates its files in the exact format needed.
Other bombs that create or can create this format:
Tasari's AddURLBomb and Tazbomb
Bo's BuyitBomb (with conversion)
Gil's CBBomb (with conversion)
My own Atlasbomb (for your site map)
(I may have missed some)
You can create Fatbomb database files yourself too, for example, using Excel or Access. As long as you keep the right format it will work fine.
Jeff