Not really getting how to call code "meta-style" from other points -- in my
file, in other files, in my "library of babel" file? I've tracked down bits
and pieces here and there, but I'm missing the big picture.

For example, this:

#+srcname: python2_env
#+begin_src emacs-lisp
  (setq org-babel-python-command "python")
  (set-face-background 'modeline "#4477aa")
#+end_src

#+srcname: python3_env
#+begin_src emacs-lisp
  (setq org-babel-python-command "python3")
  (set-face-background 'modeline "#771944")
#+end_src

Why is #+srcname being used and not just #+name? I assume these blocks will
be called later? I'm also assuming that #+call plays a role, but this page
<http://orgmode.org/manual/Evaluating-code-blocks.html> has no examples and
confused me.

This example
<https://lists.gnu.org/archive/html/emacs-orgmode/2010-09/msg00466.html> again
uses #+srcname:

. . .
* Opening
> #+srcname: opening
> #+begin_src org
> Dear Org mode users,
> #+end_src
. . .
* Closing
> #+srcname: closing
> #+begin_src org
>   Yours Truly
> #+end_src
. . .
and then

. . .
\setupdocument{
>     to = {%
>           <<to>>},
. . .
>     opening = {<<opening>>},
>     closing = {<<closing>>}
> }

I'm guessing the opening and closing are being called. But again, why
srcname and not just name? And what if my blocks had been defined somewhere
outside of this file?

LB