it may be a wild guess, but doesn't it occur to you that all the other valve games are <1000 because they came first? I mean, I am no expert on valve's naming system for their content files, but it seems like they might have that space ready for the other source games.
Plus, valve had nothing to do with the production of codename gordon, yet it is #98. It just happened to have come in the "era" of half-life 1. So, when the era of Half-Life 3 begins, it will be in the 1000's.
- Settle down...still, no guessing—ts2do 19:06, 14 Apr 2006 (PDT)
Now you are doing it.
you are changing the steam internal test app id's. No need to list anything but multiples of 10 there, we can assume that the integers are parts of the same content contained in the multiple of 10 (ie: HL2 is 220, but the content can be accessed individually in 221, 222, 223, etc).