https://issues.dlang.org/show_bug.cgi?id=13705

          Issue ID: 13705
           Summary: Named character entities with multiple code points not
                    supported
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: DMD
          Assignee: nobody@puremagic.com
          Reporter: bugzilla@digitalmars.com

They are in entity.c, but commented out:

https://github.com/D-Programming-Language/dmd/blob/master/src/entity.c#L285

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