The description of the location with on_describe(), does not seem to be part of the layers in themes settings. I would like to put this between the Exit list (X) and Object list(O) layers; but there may be a good reason why this doesn't seem possible.

Right now this isn't supported unfortunately, but I'll certainly look at being about move this around via the layout. Watch this space.

In the meantime there is a small workaround ....

start_at                 = village
locations {
   forest        : location "You are in a forest." ;
   village : location "You are in the village." ;
}
connections {
   from, direction, to = [
      village, east, forest, 
   ]
}
objects {
   lamp : object "a lamp" start_at = "village" ;
}
strings {
   some_dynamic_string : string_dynamic {(
      is_at "village" ? "You hear sounds of the village" :
      is_at "forest" ? "You hear sounds of the forest" : 
      ""
   )}
}
themes {
   my_theme : theme {
      settings {
         layout = H G D X P* "some_dynamic_string" O SEP "adv_line_red" 
      }
   }
}