Genesis includes a entire file with filter functions for genesis markup. You can view all this code in genesis > lib > functions >
The tutorials listed in this archive contain code which enables you to modify or add to the default output of different markup attributes in Genesis like classes and schema. The default code is located in the genesis > lib > functions > markup.php file.
This post contains 32 code snippets which you can use to remove or modify the default schema included in Genesis. The code enables you to