Good precautions there. Like I said in my previous post: use a virtual machine if you're tempted to try it and see what it is.
That only allows you to check whether it apparently does what it promises, but not whether it doesn't do something else it shouldn't. See: https://en.wikipedia.org/wiki/Trojan_horse_(computing
As for admin priviliges that's not really a concern as all apps require that to be installed anyway.
First of all, not all apps require that. It all depends what they do or need - and this app doesn't seem to provide any functions that would necessitate that. But even if all apps would require admin privileges, that still wouldn't mean that giving those rights to a generally untrusted piece of code wouldn't be a concern. That's actually a concern even then when the app doesn't require admin privileges, because even without those it can do serious harm. And even then when its author didn't intend it to do that.
But you're right if you cannot test it safely like I said better not risk it.
Well, as explained above, you can't be sure of its intents and dangers even if you test it. But my main concern is more that I fail to see the benefits here, while the risks are enormous. I mean it raises all flags, from being downloadable from Mega to requiring admin rights and all. And it's not that I know that this software will definitely do any harm, I just don't know why would anyone want to take all that risk by install it, when a Google search can definitely get him the same results and even more, without any (or barely any) risks associated.
I know the author writes that it's for situations where and when you can't search online... but is that a realistic concern for anyone here in 2019?
PS: Not questioning your intent or anything, just as said, the validity of risk/benefit ratio and validity of this application in 2019.