The following modules are distributed with Guile but are not documented in
this manual (other than mentioning them here). In all cases, the module is
actually included to support other modules, has
-sup in its name, and
is not very interesting on its own right (you're not missing anything).
On the other hand, some modules are undocumented even though they may or may not be interesting on their own right (we haven't figured them out yet).