[char.traits.require] p1 says:

X denotes a traits class defining types and functions for the character container type C […] Operations on X shall not throw exceptions.

It should be clarified what "operations on X" means. For example, in this patch, there was some confusion around the exact meaning of "operations on X". If it refers to the expressions specified in [tab:char.traits.req] or if it refers to all member functions of X, this should be worded in some clearer way.