developer.github.com

In a Nutshell, developer.github.com...

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  has had 6,562 commits made by 365 contributors
  representing 9,972 lines of code
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  is mostly written in Ruby
  with a very low number of source code comments
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  has a well established, mature codebase
  maintained by nobody
  with stable Y-O-Y commits
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  took an estimated 3 years of effort (COCOMO model)
  starting with its first commit in April, 2011
  ending with its most recent commit about 10 years ago