Wandering Trader Spawning?

You can check data types by listing them with system_profiler -listDataTypes and then use them to get specific info. For example to get info about chipset & RAM run system_profiler SPHardwareDataType.

I don't entirely understand what you are trying to achieve, and whatever I'm guessing, I don't think I would do it the same way, but, in any case, here's a change that makes that document compile.

\cs_new_protected_nopar:Nn \pre_key_tl_save:Nn
{
  \tl_if_empty:cF {l_cfr_#2_tl}
    {
      \tl_gput_right:No #1 { #2 = }
      \tl_gput_right:NV #1 \c_left_brace_str
      \tl_gput_right:Nv #1 { l_pre_#2_tl }
      \tl_gput_right:NV #1 \c_right_brace_str
      \tl_gput_right:Nn #1 { , }
    }
}

This seems wrong, even if I don't understand that clearly, that's, for one, overcomplicating the issue with many different parts, and also, the fact that you cannot actually do that (adding \c_left_brace_str is not adding an opening group catcode 1 { but an catcode “other”, similar to \string{). It's simpler with a plain x argument, with the correct \exp_not:*.

\cs_new_protected_nopar:Nn \pre_key_tl_save:Nn
 {
  \tl_if_empty:cF {l_cfr_#2_tl}
   {
    \tl_gput_right:Nx #1 { #2 = { \exp_not:v { l_pre_#2_tl } } , }
   }
 }

With this change it at least compiles, but I don't know if this solves all.

---

You want to add a string, and the value of a macro to another macro. The easiest way to do that is to do all at once with an x argument. It's literally doing what you wanted to do, but correct. \tl_put_right:Nx expands the second argument in an \edef, that is, it expands everything, so you only need to stop at the precise moment that you want. After substituting arguments you end with

\tl_gput_right:Nx \g_pre_img_options_tl { graphics = { \exp_not:v { l_pre_grahpics_tl } } , }

If you saw \edef\foo{graphics={foo}} you understand what the content of \foo would be: nothing expands, nor the letters, nor the “others” (“=”), nor the braces { and }. So the magic is inside \exp_not:v { l_pre_grahpics_tl }. Thanks to expl3 arguments that is exactly the same as \exp_not:V \l_pre_grahpics_tl which in turn is the same as \exp_not:n { width=\textwidth } which just stops the expansion there (\exp_not:n is \unexpanded).

That way, the line above, after the x expansion, ends up being exactly

\tl_gput_right:Nn \g_pre_img_options_tl { graphics = { width = \textwidth } , }

if it wasn't for the \unexpanded{width=\textwidth} TeX might have tried to expand \textwidth as with any other macro, which (not sure right now) might have been expanded to \dimen <number> and, in general, we don't want that expansion to happen.

Sorry, but anyone is free to edit this answer, which is anything but perfect.