WP_Customize_Setting::save()
Method: Checks user capabilities and theme supports, and then saves the value of the setting.
Source: wp-includes/class-wp-customize-setting.php:520
customize_sanitize_js_{$this->id}
Filter Hook: Filters a Customize setting value for use in JavaScript.
Source: wp-includes/class-wp-customize-setting.php:802
customize_save_{$id_base}
Action Hook: Fires when the WP_Customize_Setting::save() method is called.
Source: wp-includes/class-wp-customize-setting.php:539
WP_Customize_Setting::json()
Method: Retrieves the data to export to the client via JSON.
Source: wp-includes/class-wp-customize-setting.php:818