[ Type code = |X? ] This three-character type combination (vertical bar, X, followed by any third character A-Z) is one of the more obscure features available. It programs Ctrl+X to act as if you entered Ctrl+*, where "*" is the third character of the three-character type code. For example, the sequence |X[ would cause Ctrl+X to act like Ctrl+[ (Escape). Perhaps this would be useful if your terminal did not allow certain control sequences to be input from the keyboard.
