customList: An ST_Xstring ([ISO/IEC29500-1:2011] section 22.9.2.19) attribute that specifies a comma-delimited list of strings that specifies a custom sort order (2). The order of strings in the list specifies the sort order (2). When a cell value matches a string in the list, it is sorted ahead of the cell values that match a later string in the list, and so on for each cell in the range. MUST be ignored if sortBy is not equal to "value".
dxfId: An ST_DxfId ([ISO/IEC29500-1:2011] section 18.18.25) attribute that specifies the format identifier when sortBy equals "cellColor" or sortBy equals "fontColor". MUST NOT be present if sortBy equals "icon" or "value".
iconSet: An ST_IconSetType attribute that specifies the icon set when sortBy equals "icon". The absence of this attribute means no icon. MUST NOT be present if sortBy is not equal to "icon".
