2.4.3 UserRowNames
The following sections specify the pre-defined rows that can exist within a User section for a sheet. Each row is specified by a Row_Type child element of a User Section_Type element. Other rows can be defined through sheet extensibility.
If the N attribute of a Row_Type child element of a User Section_Type element is equal to one of the values defined in the following sections. The meaning of the Row_Type element is specified in the corresponding section.