Documentation for Issue #5920.
diff --git a/Doc/library/string.rst b/Doc/library/string.rst
index 52bd8f1..0eb1b57 100644
--- a/Doc/library/string.rst
+++ b/Doc/library/string.rst
@@ -434,7 +434,10 @@
    | ``'%'`` | Percentage. Multiplies the number by 100 and displays    |
    |         | in fixed (``'f'``) format, followed by a percent sign.   |
    +---------+----------------------------------------------------------+
-   | None    | The same as ``'g'``.                                     |
+   | None    | Similar to ``'g'``, except with at least one decimal     |
+   |         | point and a default precision of 12. This is intended to |
+   |         | match :func:`str`, except you can add the other          |
+   |         | format modifiers.                                        |
    +---------+----------------------------------------------------------+