Ligatures that might not be supported by any known fonts, otherwise unprintable characters, etc etc etc. This is for those situations where you’ve got a stream

Ligatures that might not be supported by any known fonts, otherwise unprintable characters, etc etc etc. This is for those situations where you’ve got a stream of Unicode coming in and there’s some sort of weird behavior you’re trying to figure out due to some glyph that’s not otherwise representable, ie, is that end-of-line a carriage-return, a new-line, is there a space afterwards, and did that program just include a null-character as record delimiter before the new-line??? That sort of thing.