It appears that native support for the Klingon alphabet has been removed from version 10: \[KlingonA] Syntax::tsntxi: "\"!(\[ KlingonA])\" is incomplete; more ...
I noticed that Mathematica has a set of special 'Formal' characters such as \[FormalA], \[FormalB] , etc.. In the front end, it ...
In the non-printing characters documentation, I see two named characters that are largely undocumented: \[InvisiblePrefixScriptBase] and ...