I know it's just two of the files, but taking into account the rest of the pages for the FB app in 2007, it does not seem like a lot of code. One or two people could have written and maintained a project that size. What were all the new hires doing from 2005-2007?
The company wasn't very large at that time. Probably less than 100 engineers in 2007. One person could understand the bulk of the codebase in a a reasonable amount of time.
There was way more code than you're seeing here though, note all the includes at the top.
