In the Conformance Clause for Small Group Evaluators, there is this particular clause 2.2.2(I):

"""
I)It shall support international characters for named expression identifiers.
Note: This specification does not mandate a user interface for international characters, so a resource-constrained application may choose to not show the traditional glyph (e.g., it may show the [UNICODE] numeric code instead).
"""

Problem #1: The Note is not about OpenFormula evaluators but what a hosting-specification and its implementations might provide for. The note should be removed, especially since it includes normative-provision language ("may").

Problem #2: "international characters" is not a defined concept. The syntax for named expression identifiers seems to be quite explicit. Although there are many notes in section 5.11, there is a potential conflict with the rules for case-sensitive names that must not be case-insensitive confused and some other non-note provisions.

Problem #3: The resolution of named expressions is clearly a host-dependent behavior (and the host-dependent behaviors that are tacit in section 5.11 need to be made explicitly host-dependent and simplified), so which uses of Unicode characters match with host-provided named expressions need not be resolved here.