Q:

How do I load expl3 without LaTeX (or any other format)?

\input expl3-generic %

hello, world

\bye

gives me \inf errors about undefined control sequences when processed with tex.
When processed with initex, I'm greeted with an even more puzzling error (given the very simple beginnings of expl3-generic):
$ initex
This is TeX, Version 3.14159265 (TeX Live 2014) (INITEX)
**\input expl3-generic
(/usr/local/texlive/2014/texmf-dist/tex/latex/l3kernel/expl3-generic.tex)
Runaway definition?
{expl3} \def \ExplFileDescription {L3 programming layer} \def \ExplFileDate \ET
C.
! File ended while scanning definition of \ExplFileName.
<inserted text> 
                }
<*> \input expl3-generic

? Q
OK, entering \batchmode

A:

expl3 needs etex, so you need to use etex not tex or initex --etex.

