add-file-local-variable-prop-lineadd-file-local-variable-prop-line is an interactive autoloaded Lisp function in `
files-x.el'. (add-file-local-variable-prop-line VARIABLE VALUE &optional INTERACTIVE) Add file-local VARIABLE with its VALUE to the -*- line. This command deletes all existing settings of VARIABLE (except `mode' and `eval') and adds a new file-local VARIABLE with VALUE to the -*- line. If there is no -*- line at the beginning of the current file buffer then this function adds it.