diff -r b244bf74b638 Doc/library/argparse.rst
--- a/Doc/library/argparse.rst	Sun Oct 02 13:49:05 2016 +0300
+++ b/Doc/library/argparse.rst	Sun Oct 02 16:08:09 2016 +0100
@@ -753,7 +753,9 @@
 
 * ``'append'`` - This stores a list, and appends each argument value to the
   list.  This is useful to allow an option to be specified multiple times.
-  Example usage::
+  This means that if the default value is non-empty, the default elements
+  will be present in the parsed value for the option, with any values
+  from the command line appended after those default values.  Example usage::
 
     >>> parser = argparse.ArgumentParser()
     >>> parser.add_argument('--foo', action='append')