Proposal: INTENT(NONE) indicates a dummy argument that is never referenced.
This sounds silly at first, but it is already used in some intrinsic procedures, such as the MOLD argument of the TRANSFER statement.
Generally, INTENT(NONE) is useful for aiding generic-to-specific procedure mapping, as in the TRANSFER example. It could also be used to flag intentionally-unused arguments, which are occasionally useful.
This is for instance the case when commenting lines of code, ie not using some variables, for debugging purpose, while not wishing all the verbose of the compiler saying ‘this or that has been declared but not used’.