Alt-U: Unicode Entry

Enter a Unicode character as a series of hexadecimal digits. To exit this mode, type any printable character other than a hex digit, or press Esc or End.

Characters outside the BMP are supported. For example, you can type Alt-U 1 F 4 3 1 to produce a cat face emoji.

Alt-U is the default hotkey for this action, but you can change it with EDITKEYS /K7:key.