Khronos public bugtracker – Bug 146
<unit>'s name attribute different type than all other names
Last modified: 2014-01-07 10:23:12 PST
Per Bug 9, all name attributes were to be changed to xs:token. Just confirmed that this was done for all attributes named "name" in 1.5.0 except <unit name= >, which is an xs:NMTOKEN.
Can't find any text anywhere about why this should be different. If this isn't a bug in the definition, then consider it to be a bug in the schema's <xs:documentation> for this element to explain why it must be different.