AUPreset file format used by GB/Logic

I'd like to conform to the same format that GarageBand and Logic use to create aupreset files. However upon inspection it appears that these apps are creating malformed plist documents.

Does anyone have more info? I must be missing something obvious but so far I'm unable to export in a similar way, or import for that matter.
AUPreset file format used by GB/Logic
 
 
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