2.1.753 Part 1 Section 188.8.131.52, group (OLAP Group)
a. The standard does not define limitations on the valid values for the id attribute.
Office requires that the value of the id attribute be greater than 0.
b. The standard does not define a length limitation to the value of @uniqueParent.
Office limits the value of @uniqueParent to 65535 characters.
c. The standard does not place limits on the length of @caption, @name, and @uniqueName.
Office assumes that for @caption, @name, and @uniquename, if the value of pivotCacheDefinition@createdVersion is less than 3, the maximum length of these attributes is 255 characters.