RE: [External] : Rename .dir-locals.el to .dir-locals.eld

[Drew Adams]

> >> I think we should restrict the `.el` extension for files which contain
> >> actual ELisp code rather than files that just contain text in ELisp's
> >> sexp format.  WDYT?
> >
> > 1. Why do you think so?
> >
> > 2. Isn't every Elisp sexp "code"?  How are you
> >    going to distinguish "code" from other sexps?
> 
> Again?  We already went through this discussion.  And the result is
> `lisp-data-mode`, which the major mode I'd recommend we use for
> `.eld` files.

I see.  I just now found and read what I guess
is the thread `lisp-data-mode' was discussed in:

https://lists.gnu.org/archive/html/emacs-devel/2019-10/msg00692.html

(But the JavaScript/JSON analogy given there
isn't so exact here, I expect.  IIUC, in at
least some of the expected Lisp "data" files
any and all valid Elisp syntax is to be
expected.  Not all JavaScript syntax is JSON.)

What's the criterion for such data?  Is it
that it's Lisp-`read'able without error (not
necessarily `eval'able without error)?

I still have the question "Why?" for *.eld.
(That doesn't imply an objection to it.)
What's the reason for the different extension?

Is it just so flymake or font-lock or whatever
doesn't treat list sexps as more than lists,
i.e., as function applications?

Why, please, if you don't mind.