Clarification on using safe-local-variable-values

[Andrew M. Scott]

I'm confused at how to use the new safe-local-variable-values
added on Feb 14, 2006 is supposed to work.

% emacs -Q &

C-x C-f ~/.mailrc, where ~/.mailrc is under RCS control

which has this at the bottom:

# Local Variables:
# after-save-hook: build-mail-aliases
# End:

I get prompted with a *Local Variables* buffer:

The local variables list in .mailrc
contains variables that are risky (**).

Do you want to apply it? You can type
y  -- to apply the local variables list
n  -- to ignore the local variables list
!  -- to apply the local variables list, and mark these values (*) as
      safe (in the future, they can be set automatically.)\n\n")

 ** after-save-hook : build-mail-aliases

and with minibuffer:

Please type y, n, or !:

Q1: Curiously, with my cursor now at the end of the minibuffer line,
    Emacs did not respond to C-x o or mouse (I wanted to select the
    contents of the *Local Variables* buffer for submission in this
    email). Is this intentional?

Q2: Exactly where/how is the result of option "!" stored?

    I chose option "!" and visited the ~/.mailrc file.

    C-h v safe-local-variable-values still returned nil

    yet C-h N addition hints that safe-local-variable-values 
    should be updated with my change (somewhere?):

    At the prompt, the user can choose to save the contents of this local
    variables list to `safe-local-variable-values'.  This new customizable
    option is a list of variable-value pairs that are known to be safe.
    Variables can also be marked as safe with the existing
    `safe-local-variable' property (see `safe-local-variable-p').
    However, risky variables will not be added to
    `safe-local-variable-values' in this way.

    I also looked and didn't see any update to any ~/.customize* or 
    ~/.emacs.d/* files, or any other file in ~/.

    If I kill the ~/.mailrc buffer and revisit it, I get prompted
    with the same *Local Variables* buffer scenario as the 
    first time.

Thanks,
Andy Scott

In GNU Emacs 22.0.50.1 (x86_64-unknown-linux-gnu, X toolkit)
 of 2006-03-07 on chls308
X server distributor `The XFree86 Project, Inc', version 11.0.40201000

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: C
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8
  default-enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  tooltip-mode: t
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  menu-bar-mode: t
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  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  line-number-mode: t

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<drag-mouse-1> <help-echo> <down-mouse-1> <mouse-1> 
C-g C-h v s a f e - <tab> <tab> v a <backspace> <backspace> 
e v <tab> <return> C-h v s a f e - <tab> <tab> v a 
<tab> <return> C-x o C-e C-b C-b C-b C-b <return> C-x 
1 C-s ! <down-mouse-4> <mouse-4> <down-mouse-4> <mouse-4> 
<down-mouse-4> <mouse-4> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
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