@alf131
The Product CSV import/export tool exports all products based on assigned categories. This means category export is dependent on if a product is categorized or not.
So if no product is attached to an empty category, it won’t be in the exported CSV. This is the default behavior.
I’m going to leave it open for a bit to see if anyone is able to chime in to help you out.
I can also recommend the WooCommerce Developer Resources Portal for resources on developing for WooCommerce.
You can also visit the WooCommerce Facebook group or the #developers
channel of the WooCommerce Community Slack. We’re lucky to have a great community of open-source developers for WooCommerce, and many of our developers hang out there, as well.