Character codes 63425 through 63436 (within the WL private use range) can be typed with backslash escape sequences. Despite displaying like digraphs they are single characters:
{"\!", "\@", "\%", "\^", "\&", "\*", "\(", "\+", "\/"}
{ToCharacterCode@#, StringLength@#}& /@ %
(* {"\!", "\@", "\%", "\^", "\&", "\*", "\(", "\+", "\/"}
{{{63425}, 1}, {{63426}, 1}, {{63429}, 1}, {{63430}, 1}, {{63431}, 1}, {{63432}, 1}, {{63433}, 1}, {{63435}, 1}, {{63436}, 1}} *)
These characters are not listed in the Listing of Named Characters. Calling CharacterName just returns Missing[Notavailable]. What are they used for?
