Hi marcos, just responding to old tickets for posterity. The import fields list on Trello is difficult to maintain and out of date so will be closed shortly for a custom solution for visser.com.au to clarify this.
“Import” means importing new Products
“Merge” means importing changes against existing Products
The two are listed separately as at import time we decide whether we are importing a new Product or merging Product changes and any import field must be added to both methods to be marked as fully supported.
