How can I tell which files have been added or modified compared to a "clean" WordPress installation?

Question

git

Colleagues,
I am working on the following task: there is a WordPress site that has been developed for quite a long time.
You need to determine which files/folders have been added or modified compared to a standard (clean, freshly installed) build of WordPress , so you can do things like this: install WordPress on your local machine from scratch and push the files that have been added onto it from above / modified on the live site to get a local working copy of it.
Perhaps a significant detail: "different" files are supposed to be kept in a git repository and synchronize the local and production copy of the site through it.
Thanks in advance for your replies!

Answer 1

1. Throw a clean one into git
2. Make a commit.
3. Push the modified one into git on top of the clean one.
4. Make a commit.
5. Make a diff.
6. Get a patch.
7. Roll the patch as needed.
But I do not really understand why modify the kernel. Not enough hooks?

Answer 2

An important question: is the working site now on the latest version of WordPress or on some old one?