Filesystems^H directories and case-insensitivity

If you thought case-insensitivity was ill-conceived...

As a coincidence I recently got hurt by this NTFS "feature": *per-directory* case-sensitivity
https://github.com/vector-of-bool/vscode-cmake-tools/issu...

In other words: filenames are case sensitive in some directories but not in other directories next or below them on the very same filesystem.