Filenames in GIT commands - case sensitive or not?

Question

git

create a file for example README.txt
then write
git add readme.txt
the command is successful. Those. git seems to have seen the file, otherwise it would have thrown an error a la:
fatal : pathspec 'readme.txt' did not match any files But then if we commit or just check the status, we
see Untracked files: README.txt
, why didn't it throw an error on "git add readme.txt" then?

Answer 1

Under linux, they are definitely case-sensitive.
It cannot be otherwise. Since it is possible to create two different files README.md and readme.md