WP_Customize_Setting::preview()
Method: Add filters to supply the setting’s value when accessed.
Source: wp-includes/class-wp-customize-setting.php:319
customize_update_{$this->type}
Action Hook: Fires when the WP_Customize_Setting::update() method is called for settings not handled as theme_mods or options.
Source: wp-includes/class-wp-customize-setting.php:704
customize_preview_{$this->id}
Action Hook: Fires when the WP_Customize_Setting::preview() method is called for settings not handled as theme_mods or options.
Source: wp-includes/class-wp-customize-setting.php:400
WP_Customize_Setting::_update_theme_mod()
Method: Deprecated method.
Source: wp-includes/class-wp-customize-setting.php:716