2.1.1689 Part 1 Section, scr (Script)

a.   The standard says that the script element is used to map ASCII values to the appropriate Unicode range.

Word uses the script element and the style element to map Unicode values to Math Alphanumeric Unicode values.

b.   The standard implies that the val attribute is optional.

Word requires this attribute.

c.   The standard does not specify a default value for scr.

In Word, the default value for scr is roman.