The optional normal attribute defines the normal of the plane for drawing a leader head with type SYMBOL_CROSS.
Source
<xs:complexType name="LeaderHeadFormType"><xs:annotation><xs:documentation>The LeaderHeadFormType defines the form of a leader head.</xs:documentation></xs:annotation><xs:simpleContent><xs:extension base="LeaderHeadFormEnumType"><xs:attribute name="normal" type="D3Type"><xs:annotation><xs:documentation>The optional normal attribute defines the normal of the plane for drawing a leader head with type SYMBOL_CROSS.</xs:documentation></xs:annotation></xs:attribute></xs:extension></xs:simpleContent></xs:complexType>
<xs:attribute name="normal" type="D3Type"><xs:annotation><xs:documentation>The optional normal attribute defines the normal of the plane for drawing a leader head with type SYMBOL_CROSS.</xs:documentation></xs:annotation></xs:attribute>