This will be indispensable while camping hogger on Kronos II.
It also works for players but it's named npcscan because that's where the iconic animation is copied from.
While camping Nazjak on the Nost PvE server I was sorely missing an addon like retail _NPCScan which alerts the player when certain NPCs are nearby - so I made one.
The detection method from retail (testing if the model is in the WDB by using a unit hyperlink) doesn't work in Vanilla afaik (or if so I would love to know how). On the other hand targeting is not a protected function so that can be used instead (which means no cache clearing required, but probably a smaller detection range).
I've exactly copied the alert of the retail version (https://www.youtube.com/watch?v=iYeXY5RSPi0) but the backend is kept very simplistic.
Also, showing your target on the minimap is probably not possible in vanilla (?).
There are two commands:
/npcscan lists the current targets
/npcscan name toggles name
When a target is detected it is removed and you have to add it again.