Running git 2.21.0 on Windows with certain invalid file names like "c:\root.txt" (see https://github.com/jmandel/local-path-test as a test case), I get an expected "invalid path" error when I clone the repository.
But if I actually have a file at this path (i.e., outside of the git working tree, at root of my file system) then I instead receive a different error message:
$ touch /c/root.txt $ git clone https://github.com/jmandel/local-path-test.git
> error: Untracked working tree file 'c:\root.txt' would be overwritten by merge.
This error message is misleading, in that (if I understand correctly) there's actually no danger of my local file (which is *not* in the working tree at all) being overwritten.
Best, Josh