No, you don't. Read again his reply, he clearly points to a mod that does exactly this. Stop being hostile, people are trying to help.
Let's go over this again:
You said you want the heading of the ship: it's already there on the navball, as it's been pointed out. If you want it somewhere else on the screen, KER has got your back, and it also has for ship pitch.
You also said you want the heading and elevation of the target relative to the ship: again, KER has got your back.
You also said you want to be able to target a part of terrain, and show heading and elevation of that relative to the ship; Waypoint Manager has got you covered, as it's been pointed out.
You also want "the heading and elevation of the mouse cursor". This doesn't exist, I'm sorry, it's just not a thing. The mouse cursor is an object on the screen, not the 3D world. You can have a direction projected from the game camera, but unless you're in IVA, that information has no relation to the ship's position, and zero use for navigating.
If you already know of all these and they still don't do what you want, then please, can you explain better what you really want? "Just two numbers" is not an answer, we've given you plenty of numbers already.