I think the middle photo shows a metal insert embedded in the carbon, with teeth to stop it rotating within the resin when the brake is applied / when the mechanic gorillas it.
(Here's something similar on a carbon crank)
@grams started
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I think the middle photo shows a metal insert embedded in the carbon, with teeth to stop it rotating within the resin when the brake is applied / when the mechanic gorillas it.
(Here's something similar on a carbon crank)