C<\X> matches quite well what normal (non-Unicode-programmer) usage
would consider a single character. As an example, consider a G with some sort
-of accent mark over it (a diacritic). There is no such single character in
-Unicode, but something like one can be constructed by using a G followed by a
-Unicode combining accent, and would be displayed by Unicode-aware software as
-if it were a single character.
+of diacritic mark, such as an arrow. There is no such single character in
+Unicode, but one can be composed using a G followed by a Unicode "COMBINING
+UPWARDS ARROW BELOW", and would be displayed by Unicode-aware software as if it
+were a single character.
Mnemonic: eI<X>tended Unicode character.