Git config files: Best practice - windows

Question

I managed somehow to make Git running with Github and now (a year later) I would like to teach the group how they can do the same. I learned quite a lot from here, but even with the answer, some things remain unclear. Please apologize, if I didn't got it from the git reference
Questions:
Is there a best practice, which parameters should show up in which config file?
... Continued from my example below:
I marked the parts which I can access via --system, --global and --local. Does anybody know where the first part belongs to?
Green is everything, where I think, it is ok (with my very limited knowledge).
Red is strange as it exists twice
When I run git config --list --show-origin I get the following result:
Edit #Code-Apprentice:
From git-bash
$ git config --list --show-origin --system
file:"C:\\Git\\mingw64/etc/gitconfig" credential.helper=manager
and cmd
>git config --list --show-origin --system
file:"C:\\Git\\mingw64/etc/gitconfig" credential.helper=manager
Git output as code:
file:"C:\\ProgramData/Git/config" core.symlinks=false # ... see .git/config
file:"C:\\ProgramData/Git/config" core.autocrlf=true
file:"C:\\ProgramData/Git/config" core.fscache=true
file:"C:\\ProgramData/Git/config" color.diff=auto
file:"C:\\ProgramData/Git/config" color.status=auto
file:"C:\\ProgramData/Git/config" color.branch=auto
file:"C:\\ProgramData/Git/config" color.interactive=true
file:"C:\\ProgramData/Git/config" help.format=html
file:"C:\\ProgramData/Git/config" http.sslcainfo=C:/Git/mingw64/ssl/certs/ca-bundle.crt
file:"C:\\ProgramData/Git/config" diff.astextplain.textconv=astextplain
file:"C:\\ProgramData/Git/config" rebase.autosquash=true
file:"C:\\Git\\mingw64/etc/gitconfig" credential.helper=manager # ... see file:C:/Users/myname/.gitconfig
file:C:/Users/myname/.gitconfig filter.lfs.clean=git-lfs clean %f
file:C:/Users/myname/.gitconfig filter.lfs.smudge=git-lfs smudge %f
file:C:/Users/myname/.gitconfig filter.lfs.required=true
file:C:/Users/myname/.gitconfig user.name=My name
file:C:/Users/myname/.gitconfig user.email=my.name#domain.com
file:C:/Users/myname/.gitconfig credential.helper=wincred
file:C:/Users/myname/.gitconfig alias.hist=log --pretty=format:'%h - %an, %ad: %s' --graph --date=short
file:C:/Users/myname/.gitconfig difftool.kdiff3.cmd='C:/Program Files/KDiff3/kdiff3' $LOCAL $REMOTE
file:C:/Users/myname/.gitconfig difftool.kdiff3.keepbackup=false
file:C:/Users/myname/.gitconfig difftool.kdiff3.trustexitcode=false
file:C:/Users/myname/.gitconfig merge.conflictstyle=diff3
file:.git/config core.repositoryformatversion=0
file:.git/config core.filemode=false
file:.git/config core.bare=false
file:.git/config core.logallrefupdates=true
file:.git/config core.symlinks=false
file:.git/config core.ignorecase=true
file:.git/config core.hidedotfiles=dotGitOnly
file:.git/config remote.origin.url=https://github.com/repo/Rettung-ZCH
file:.git/config remote.origin.fetch=+refs/heads/*:refs/remotes/origin/*
file:.git/config branch.master.remote=origin
file:.git/config branch.master.merge=refs/heads/master
file:.git/config branch.dev1.remote=origin
file:.git/config branch.dev1.merge=refs/heads/dev1
file:.git/config branch.dev2.remote=origin
file:.git/config branch.dev2.merge=refs/heads/dev2

Answer 1

Is there a best practice, which parameters should show up in which config file?
This is totally up to you, whether you want a setting only on one repository, on all repositories you access with your user account or on all repositories on this machine (each time of course only if not overwritten from a lower config level).
I marked the parts which I can access via --system, --global and --local. Does anybody know where the first part belongs to?
As far as I remember these are the default values of the Git for Windows client and are on (or rather above) the system settings level. You can list and change them with git config --file c:\ProgramData\Git\config --list and so on.
Green is everything, where I think, it is ok (with my very limited knowledge).
As I said, totally up to you. The local green settings are most probably only useful on the local level, yes. For me user.email for example is not set on global level on my work box, as I work on private and corporate repos and use different addresses there. By not configuring either on the global level I am reminded on local level to set it when doing the first commit.
Red is strange as it exists twice
You can have each setting on each level, lower level overwriting value of upper levels, this is perfectly legal. You can e. g. set for all users on the system to use credential.helper=manager but for your user to use credential.helper=wincred like you have it in your example.

Answer 2

For Windows there should be following global settings:
rem always have Linux line endings in text files
git config --global core.autocrlf input
rem support more than 260 characters on Windows
rem See https://stackoverflow.com/a/22575737/873282 for details
git config --global core.longpaths true
rem some color and diff tweaks
rem Use SVN's ||| also in git
rem See https://git-scm.com/docs/git-config#Documentation/git-config.txt-mergeconflictStyle for details
git config --global merge.configStyle "diff3"
git config --global color.diff.new "green bold"
git config --global color.status.updated "green bold"
git config --global color.branch.current "green bold"
rem Sort branches at "git branch -v" by committer date
git config --global branch.sort -committerdate
(The hints at https://stackoverflow.com/a/24045966/873282 are obsolete)

Answer 3

Git will override more global settings with more local ones. The duplicated (red) ones in your output guarantee consistency at a more local level if the more global value is ever changed.