By the way, forgive this ignorant question, but is the Emacs source code written in C or in C++?

On Sat, Aug 12, 2017 at 3:15 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> From: Itai Berli <itai.berli@gmail.com>
> Date: Sat, 12 Aug 2017 15:08:53 +0300
> Cc: Emacs developers <emacs-devel@gnu.org>,
> Tino Calancha <tino.calancha@gmail.com>
>
> What's the difference between emacs and bootstrap-emacs?

Normally, none. They are only different during a bootstrap build:
bootstrap-emacs has the Lisp files in source form, before they were
byte-compiled.