[Voted into WP at March, 2010 meeting.]

Proposed resolution (February, 2010):

Change 5.3.1 [lex.charset] paragraph 3 as follows:

...The execution character set and the execution wide-character set are implementation-defined supersets of the basic execution character set and the basic execution wide-character set, respectively. The values of the members of the execution character sets and the sets of additional members are implementation-defined, and any additional members are locale-specific.

According to 5.3.1 [lex.charset] paragraph 3,

The values of the members of the execution character sets are implementation-defined, and any additional members are locale-specific.

This makes it sound as if the locale determines only whether an extended character (one not in the basic execution character set) exists, not its value (which is just implementation-defined, not locale-specific). The description should be clarified to indicate that the value of a given character can vary between locales, as well.