The site map starts with _0 for each individual module very cool indeed. It appears even though Google uses 50,000 as a limit for a site map this breaking down for each is quite clever indeed. It also appears that 20,000 is a trigger to auto generate a _1 for an individual module which will allow the module to never be faced with the 50,000 submission limit? Quite clever indeed am I correct in this humble observation? Any reason 20,000 was used?