In the Products Variations panel of the product screen there are quick edit options for values related to the product variations, however, when you have a Digital Download (Product Kind), the only way to set the File URL is to manually click on the "More Info" icon and edit it in the modal dialogue.
It's impossible to tell, looking at the list of variations, which records have or do not have values for the File URL.
Is there a quick way to add this field?
Also, just as a general UI issue, when you have a Digital Download product, you probably don't need the "Inventory" column. It makes far more sense to have the File URL field.
If there isn't an easy way to do this, please point me to a hook I can use to add the column to the table output and an example from the codebase where you used the quick-edits for the variation values and I will write a plugin to modify the columns.
Ultimately it would be nice to be able to select these ourselves as individual users have different needs.