What is a "really cool" addition?

Well, it's not really that cool by itself, it does save some work.
I was using a bit of hyperbole given the nature of posts here.
But if you were genuinely asking about the feature...

Nifty. I've always shied away from 3rd party tools but maybe I'll check this out.

I use the auto indent, multiple cut and paste and this close all the time. The search/find is pretty good, in that you can see all the lines of code at once, instead of one at a time. Also, the adding blocks of stored code, like the error handling comes in very handy for standardized code. There's a lot more, some of which I have no clue what it does.

As far as I can tell, MZ-Tools sits on your PC and interacts with the VBA Editor. If you send an .accdb or .accde file, there isn't anything in the file from MZ-Tools that would affect another person's running of the file.

MZ-Tools

So it's basically a developer-only tool. Got it. I'll add it to my llllloooooonnnnnnnnnnggggg list of things to check out.

Cool