Unitframe for the target of the mouseover target

[kamaz]

https://www.wowinterface.com/downloa...verTarget.html

Played vanila WoW and there was this awesomely useful addon when tanking. With some tweaks it worked all the way to mists of pandaria. It adds additional unitframe next to the unitframe in the lower right on the screen that shows the target of what you hover your mouse over (there is a screenshot there in the link).

I can find only this version and i know nothing about how to make addons, but it looks really simple. Can someone make a working version of this for the current wow classic please?