diff --git a/tools/llvmc/doc/LLVMC-Reference.rst b/tools/llvmc/doc/LLVMC-Reference.rst
index aa97703..4653e0e 100644
--- a/tools/llvmc/doc/LLVMC-Reference.rst
+++ b/tools/llvmc/doc/LLVMC-Reference.rst
@@ -368,7 +368,8 @@
      (switch_option "E", (extern))
      ...
 
-See also the section on plugin `priorities`__.
+If an external option has additional attributes besides 'extern', they are
+ignored. See also the section on plugin `priorities`__.
 
 __ priorities_