diff --git a/README.md b/README.md
index 35bd8821..3ff5bee2 100644
--- a/README.md
+++ b/README.md
@@ -149,7 +149,8 @@ On the command line, options can be given as:
 * `--file filename` (space)
 * `--file=filename` (equals)
 
-Extra positional arguments will cause the program to exit, so at least one positional option with a vector is recommended if you want to allow extraneous arguments
+Extra positional arguments will cause the program to exit, so at least one positional option with a vector is recommended if you want to allow extraneous arguments.
+If you set `.allow_extras()` on the main `App`, the parse function will return the left over arguments instead of throwing an error.
 If `--` is present in the command line,
 everything after that is positional only.