What's this component in Leonardo?

Hi guys,

I'm confused about this one component right next to the DC jack connector pin (see picture). I can't find it in the official schematics. It is in some product pictures though. It has a marking "KNW 4o". I know it is not the voltage regulator, that is the larger component with a big copper pour.

Anyone has any idea what it is and/or what its purpose is? Cheers.

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Thanks. Never seen a 3-pin diode before. That's why I was confused :o

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