clarify implications for the `require` keyword

README.md

@@ -69,6 +69,11 @@ them in Teliva and let people use regular Lua. Or other platforms!
   they have access to a (color, UTF-8) text-mode window for printing text to,
   and a keyboard for reading unbuffered keystrokes from.
 
+- Teliva doesn't use files, so the `require` keyword no longer makes sense.
+  You get some libraries preloaded (see below). Beyond those, apps should
+  include all Lua code they want to use. There's no affordance for adding
+  native (non-Lua) libraries.
+
 - I want to provide sandboxed access to system resources (file system,
   network, etc.) which will likely create incompatibilities with the standard
   library. I'm disinclined to try to ‘improve’ on Lua syntax,