Function wt_directory_arg 

pub fn wt_directory_arg(dir: &str) -> String

The -d argument of wt, passed through unchanged. MEASURED on Windows 11 with wt: a bare C:\ opens the drive root, while the C: this once produced opens the drive’s current directory (C:\WINDOWS\system32 there). The trailing-backslash worry applies only to a hand-quoted "C:\", and Command quotes only arguments that contain whitespace, which a drive root never does.