RE: [External] : Re: Which Elisp types are mutable?

[Drew Adams]

> In Emacs Lisp, typical immutable objects are symbols, keywords, numbers

We've been around this block a few times already,
and I don't really want to stir the pot here.

But I'll mention that a Lisp symbol is a kind of
mutable "object".  It has various properties, some
of which are predefined (whether or not they have
non-nil values) and any number of which others can
be created.  Predefined properties include the
symbol name, value as a variable, and value as a
function.

All except the symbol name can be changed.  Is a
symbol something immutable?  Not IMO, but the
answer depends on what one means by "immutable".

https://www.gnu.org/software/emacs/manual/html_node/elisp/Symbol-Components.html