2.1.1912 Part 4 Section 8.2.1, schema (Custom XML Schema Reference)
a. The standard places no restrictions on the length of the uri attribute.
Word restricts the length of this attribute to 255 characters.
b. The standard places no restrictions on the length of the manifestLocation or the schemaLocation attribute.
Word restricts the length of these attributes to 2083 characters.
c. The standard does not state that the schema and schemaLibrary information might not be round-tripped.
Word does not guarantee that the schema or schemaLibrary elements will be round-tripped; validation or security verification might result in this data being removed.