Yes. The old Path module's `.filetype()` method returned a string with a `.` prefix, e.g. `".txt"`. The new Path module's `.extension()` method does not, it just returns `"txt"`. So `os::consts::*_SUFFIX` is now intended for when you're constructing a filename via string manipulation, and `os::consts::*_EXTENSION` is for when you're using the Path module's `.extension()` and `.set_extension()` methods.