The `do_meta_boxes()` function in WordPress allows developers to display meta boxes on the screen by taking in a screen identifier, context, and data object
The `filter_default_option()` function in WordPress allows developers to customize the default values for options by filtering the original default value returned by the `get_option()` function
The `get_default_block_editor_settings()` function in WordPress allows developers to retrieve and modify the default block editor settings, including adding or removing custom options like colors, fonts, and image sizes
The `get_custom_header_markup()` function in WordPress retrieves the markup for a custom header, allowing developers to modify or display it in their themes