how to change book format icons

For reasons that are out of my understanding and ability to change, every kfx book I bring into Calibre turns into KFX-ZIP. I understand that for the rest of the world this generally means that the book hasn't been drm unlocked, but for whatever reason, my books that are unlocked still say they are KFX-ZIP.

Im tired of looking at a question marked icon for the book format when all the other formats has a nice icon.

How can I change this?

Will be willing to have the standard KFX icon if it's possible to redirect it to that.