Get your own copy
Don't hesitate! Just download and test it all by yourself for free!
If this option is set to true some accessibility warnings will be presented to the user if they miss specifying that information. This option is set to true by default, since we should all try to make this world a better place for disabled people. But if you are annoyed with the warnings, set this option to false.
tinyMCE.init({
...
accessibility_warnings : false
});
Search documentation.