I got the 105 disc groupset which had the same description, and it's just a normal mount on the rear derailleur. I wonder if it's referring to the front derailleur, which is braze-on.
It's referring to the rear derailleur which is direct mount but they always come with the extra hanger knuckle as standard.
@joeae started
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I got the 105 disc groupset which had the same description, and it's just a normal mount on the rear derailleur. I wonder if it's referring to the front derailleur, which is braze-on.