Hey,
I've looked at the code and it's quality of most of these projects at some point in the last two years, and have to say this graph is much in line with my impressions. And with what the "knowledgeable" people at PHP conferences and meetups convey. Want an example of bad code? Wordpress! Want one of good code? Symfony or Doctrine! Sadly enough MediaWiki seems to be entirely absent as a topic or even something to rant about at such meetups and conferences.
It's probably a useless statistic
It's based on SensioLabsInsight, which I personally quite dislike. ScrutinizerCI is hands down better at spotting issues (way to many false positives on SensioLabsInsight).
Good to know we still have less technical debt than WordPress. ;)
Perhaps not the best standard to set for oneself :)
Cheers
-- Jeroen De Dauw - http://www.bn2vs.com Software craftsmanship advocate Evil software architect at Wikimedia Germany ~=[,,_,,]:3