How to check what files have been customised in /etc?

[Grizzly]

14 December 2020  at 0:16, Karl Auer wrote:
Re: How to check what files have be (at least in part)

>It's a bit late to use it now in your (OP's) case, but if you set up tripwire
>on a clean system, it does an excellent job of detecting changes from then on. 

Reminds me of asking for directions in Glasglow (I'm not local there) and been 
told

"To get there, I would not start from here"