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

[Drew Adams]

> And I'll note in passing that both the Info node ‘(elisp)Intro Eval’
> and the glossary of the Common Lisp HyperSpec find this idea common
> enough to assign it a short name. A ‘form’ is an object meant to be
> evaluated. Every form is an object, but not every object is a form
> (depending on context). The separation of reading and evaluation
> is also called out specifically in the above Info node, and there's
> even a footnote which I read as unlinking the ‘sexp’ term from the
> expectation of evaluation (but the context is ambiguous).

That's precisely the way to speak of it.
Readable without error, not necessarily
evalable without error.  That's one way
to gauge probable intention ("meant to
be", "expectation of evaluation").