diff --git a/libgimp/gimp.c b/libgimp/gimp.c
index e98819db03..aea24b2242 100644
--- a/libgimp/gimp.c
+++ b/libgimp/gimp.c
@@ -1341,6 +1341,8 @@ gimp_wm_class (void)
  * Returns the display to be used for plug-in windows.
  *
  * This is a constant value given at plug-in configuration time.
+ * Will return #NULL if GIMP has been started with no GUI, either
+ * via "--no-interface" flag, or a console build.
  *
  * Return value: the display name
  **/