What are they?
Category Specific fields are fillable options that can populate based on product data. They can be required and vary based on the selected category. Because category is market dependent, the category-specific fields will be market dependent as well.
Below is an example of a required category-specific field. Note the red asterisk.
You may run into errors if a specific field is not filled out, the error will look something like "The item specific FIELDNAME is missing." where FIELDNAME will be the actual field that is missing. In order to resolve this, just add data to the field, and you will be all good! Screenshot below for clarity.
To do this quicker in bulk, you can use the Missing Category Specific template to fill out your missing values. Required values will have a yellow colored cell, so you can just focus on those when looking over the template.
If you have any other questions regarding this process, feel free to reach out to Listing Mirror support.