Main::add_ui()
Method: Adds UI control.
Source: inc/customizer/options/main.php:77
Form_Fields::sanitize_button_type()
Method: Sanitize Button Type option.
Source: inc/customizer/options/form_fields.php:617
Layout_Single_Post::section_single_post()
Method: Add customize section
Source: inc/customizer/options/layout_single_post.php:56