Document --argumentfile usage limitations.
@@ -427,6 +427,14 @@ the command line growing too long.
Argument files are taken into use with :option:`--argumentfile (-A)` option
along with possible other command line options.
+.. note:: Unlike other `long command line options`__, :option:`--argumentfile`
+ cannot be given in shortened format like :option:`--argumentf`.
+ Additionally, using it case-insensitively like
+ :option:`--ArgumentFile` is only supported by Robot Framework 3.0.2
+ and newer.
+
+__ `Short and long options`_
+
Argument file syntax
~~~~~~~~~~~~~~~~~~~~
