What exactly are empty prefabs as the asset store decline reason ?

I get this automated decline reason constantly when I submit my asset to publish: "Prefabs cannot be empty, please make sure that you set up your prefabs correctly".
There are no empty or corrupt prefabs in my project, What is meant by "empty prefab" here? A Gameobject that has no children and only consists of a transform component?

 

I'm writing in case anyone has the same problem, I deleted the declined project draft, created a new draft in the publisher interface and rewrote items such as metadata, key images and videos, finally uploaded the same package, it's been 5 days now and it's still under review, I think it went through the automated system. Previously, it was rejected within half an hour as "there is an empty prefab".