Application icons in .webp - not working

If the application uploaded to the repository has an icon in .webp (ic_launcher.webp) and not in .png (ic_launcher.png), the application icon is not displayed either on the web or in the F-Droid application.

As I understand it, fdroidserver is responsible for this in repomaker

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information