Explanation

Box 1: AuditDatePicker
Constructor: Constructor of the code component.
Box 2:DateandTime.DateOnly
Box 3: bound
usage: Has two properties, bound and input. Bound properties are bound only to the value of the field. Input properties are either bound to a field or allow a static value.
Reference:
https://docs.microsoft.com/en-us/powerapps/developer/component-framework/manifest-schema-reference/manif
https://docs.microsoft.com/en-us/powerapps/developer/component-framework/implementing-controls-using-type