How can I export a custom variable from a product, added to the store by another module?

To do this, go to the module settings:


then list the variables separated by commas in the field below:



the variables must be listed according to the structure object_name.variable_name, so e.g. if some other module added an override for the Product class at the path:
override/classes/Product.php
and in this file added, e.g., a variable additional_title, then in the field below in the exporter module:


this variable should be listed as:
product.additional_title


then this variable can be selected in the export data: