And more importantly, how can this be prevented?
echo tracked > tracked.txt
git add tracked.txt
git commit tracked.txt -m "tracked"
echo untracked > untracked.txt
ls -l
total 2
-r--r--r-- 1 My Name 1049089 8 Dec 2 09:17 tracked.txt
-rw-r--r-- 1 My Name 1049089 10 Dec 2 09:18 untracked.txt
git checkout master -- tracked.txt
ls -l
total 2
-r--r--r-- 1 My Name 1049089 8 Dec 2 09:17 tracked.txt
-r--r--r-- 1 My Name 1049089 10 Dec 2 09:18 untracked.txt
config
[core]
repositoryformatversion = 0
filemode = false
bare = false
logallrefupdates = true
symlinks = false
ignorecase = true
.gitattributes
* filter=lfs diff=lfs merge=lfs -text lockable
.gitattributes -filter -diff -merge -text
.gitattributes export-ignore
README.md export-ignore