Master SKUs are the unique values you assign to your products in Skubana. They can be changed at any time if needed.
Listing SKUs, on the other hand, are the unique values you assign to your products in your sales channels. If you sell a product in multiple listings in a marketplace, you will have more than one listing SKU for that product in that marketplace.
Create master SKUs for your products in Skubana, then link these SKUs to your listing SKUs in your sales channels. Skubana will then be able to associate your listing SKUs to your master SKUs for real-time inventory synchronization with your various sales channels.