It is all marketing
1st week - Super Wildcard Weekend - the wildcard teams get a chance to advance to the next round. Now called "Super" as there are six games instead of 4, and spread out over 3 days.
2nd week - Divisional Round - At least 1 division champion plays, the #1 seed. Note that, when they were six teams in the playoffs, the top 2 division champions had byes and would host this round of games, so the terminology it is something of a carryover. In theory, the division champions should all be here, But, On Any Giving Sunday...
Any wild card teams good enough to beat a division champion qualify for the Divisional Round.
3rd week - Championship Sunday - the games determine the conference champions and Super Bowl opponents.
Remember, they paid folks big bucks to come up with this nomenclature...
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