2.1.578 Part 1 Section 18.2.19, sheet (Sheet Information)

a.   The standard does not place any restrictions on the value for the name attribute.

Office requires that the name attribute be less than or equal to 31 characters in length and follow the character limitations for sheet-name and sheet-name-special in Formulas ("[ISO/IEC-29500-1] §18.17").

b.   The standard does not place any restrictions on the value for the sheetId attribute.

Office requires that the sheetId attribute be between 1 and 65534 inclusive.

c.   The standard does not place any restrictions on the value for the id attribute.

Office requires that the id attribute be 255 or less characters in length.

d.   The standard states that sheet names are unique.

Office requires that sheet names are case-insensitive unique in any locale.