How to edit a listing with no edit tabs at top?

Usually when editing a listing you have the top tabs to edit details, from ‘Product Details’, ‘Images’, ‘Offers’, etc.

Other times those tabs do not exist and the ‘main’ SKU that usually would have these details are not available due to needing to edit specific details on the SKU in a different country’s marketplace.

How do you go about making those edits?

Can this only be done via Flat Files? I’d prefer the ease of using the website interface if possible.

Any advice is appreciated