On Tue, 20 Jun 2017 08:40:38 +0900, Katsumi Yamaoka wrote:
> , but I haven't investigated why binding enable-local-variables
> to nil is not effective thoroughly.  I'll do it.

What tries to eval local variables is `run-mode-hooks', that runs
in the buffer containing the CONTRIBUTING.md contents.

,---- a Lisp backtrace
| hack-local-variables-confirm(((eval message "Coucou"))\
| 	((eval message "Coucou")) nil nil)
| hack-local-variables-filter(((eval message "Coucou")) nil)
| hack-local-variables(no-mode)
| run-mode-hooks()
| fundamental-mode()
| set-buffer-major-mode(#<buffer  *temp*>)
| set-auto-mode()
| mm-display-inline-fontify((#<buffer  *mm*-519429>\
| 	("text/plain" (charset . "iso-8859-1"))\
| 	quoted-printable nil\
| 	("inline" (filename . "CONTRIBUTING.md"))\
| 	nil nil nil))
`----

Why binding `enable-local-variables' to nil is not effective is
that `fundamental-mode' runs `kill-all-local-variables':

(defun fundamental-mode ()
  "Major mode not specialized for anything in particular.
Other major modes are defined by comparison with this one."
  (interactive)
  (kill-all-local-variables)
  (run-mode-hooks))

It kills `enable-local-variables' which `mm-display-inline-fontify'
makes buffer-local.  So the right solution would be to bind it
globally: