The required n attribute is the number of Id elements in this array.
Source
<xs:element name="ComponentIds" type="ArrayReferenceType"><xs:annotation><xs:documentation>The ComponentIds element is an array of component identifiers present in this product definition.</xs:documentation></xs:annotation></xs:element>
The optional size attribute defines a recommended size for visualization of an infinite drawable element such as plane, cylinder, axis, etc., or objects without explicit geometric parameters (e.g. coordinate system).
The optional transparency attribute defines the transparency property of a model entity.
Source
<xs:complexType name="FolderAssemblyType"><xs:annotation><xs:documentation>The FolderAssemblyType is the assembly folder type. It contains a set of entities that define the assembly.</xs:documentation></xs:annotation><xs:complexContent><xs:extension base="FolderPartAssemblyBaseType"><xs:sequence><xs:element name="ComponentIds" type="ArrayReferenceType"><xs:annotation><xs:documentation>The ComponentIds element is an array of component identifiers present in this product definition.</xs:documentation></xs:annotation></xs:element></xs:sequence></xs:extension></xs:complexContent></xs:complexType>