Some pretty poor categorization of some subreddits in there. gamesofthrones, mylittlepony, thewalkingdead, and BigBrother are in sports (asoiaf is in entertainment). sysadmin and techsupport are in hobbies/occupations while buildapc is in tech section. tumblrinaction, kotakuinaction, and blackpeopletwitter are in entertainment. DebateReligion is in news/politics, not discussion (with other debate subreddits) or lifestyle (with other religion subreddits).

The hierarchy is on GitHub: https://github.com/MetASnoo/Subreddit-Directory-Skeleton/blo...

But it's not in a structured format and tough to verify. There's no methodology for the current organization, and it doesn't look like it matches the actual graph.