14.8.2.22 :tangle-mode

The tangle-mode header argument controls the permission set on tangled files. The value of this header argument will be passed to set-file-modes. For example, to set a tangled file as read only use :tangle-mode (identity #o444), or to set a tangled file as executable use :tangle-mode (identity #o755). Blocks with shebang (shebang) header arguments will automatically be made executable unless the tangle-mode header argument is also used. The behavior is undefined if multiple code blocks with different values for the tangle-mode header argument are tangled to the same file.