Any escape sequence \X with X not in the list below
emits a warning, printing glyph X.
\: Using Symbols\!: Diversions\": Comments\#: Comments\$: Parameters\$*: Parameters\$0: Parameters\$@: Parameters\$^: Parameters\%: Manipulating Hyphenation\&: Ligatures and Kerning\': Using Symbols\): Ligatures and Kerning\*: Strings\,: Ligatures and Kerning\-: Using Symbols\.: Character Translations\/: Ligatures and Kerning\0: Page Motions\:: Manipulating Hyphenation\<RET>: Line Control\<SP>: Page Motions\?: Diversions\\: Character Translations\^: Page Motions\_: Using Symbols\`: Using Symbols\a: Leaders\A: Identifiers\b: Drawing Requests\B: Expressions\C: Using Symbols\c: Line Control\D: Drawing Requests\d: Page Motions\E: Character Translations\e: Character Translations\f: Font Positions\F: Font Families\f: Changing Fonts\g: Assigning Formats\h: Page Motions\H: Artificial Fonts\k: Page Motions\L: Drawing Requests\l: Drawing Requests\M: Colors\m: Colors\N: Using Symbols\n: Auto-increment\n: Interpolating Registers\O: Suppressing output\o: Page Motions\p: Manipulating Filling and Adjusting\r: Page Motions\R: Setting Registers\s: Changing Type Sizes\S: Artificial Fonts\t: Tabs and Fields\u: Page Motions\V: I/O\v: Page Motions\w: Page Motions\X: Postprocessor Access\x: Manipulating Spacing\Y: Postprocessor Access\Z: Page Motions\z: Page Motions\{: if-else\|: Page Motions\}: if-else\~: Page Motions