K_K4 (reference) in projects: vim-8.2.3635

412 #define K_K4		TERMCAP2KEY('K', 'G')	// keypad 4  macro

1000     {K_K4,		(char_u *)"k4"},

1431 	case K_K4:		key = VTERM_KEY_KP_4; break;  in term_convert_key()

/vim-8.2.3635/src/
H A D	keymap.h	`412 #define K_K4 TERMCAP2KEY('K', 'G') // keypad 4 macro`
H A D	term.c	`677 {K_K4, "\316\352"}, 780 {K_K4, IF_EB("\033Ot", ESC_STR "Ot")}, // keypad 4 975 {K_K4, IF_EB("\033Ot", ESC_STR "Ot")}, // keypad 4 1309 {K_K4, "[K4]"},`
H A D	misc2.c	`1000 {K_K4, (char_u *)"k4"},`
H A D	getchar.c	`1794 case K_K4: c = '4'; break; in vgetc()`
H A D	terminal.c	`1431 case K_K4: key = VTERM_KEY_KP_4; break; in term_convert_key()`