If a spawn egg has a custom EntityTag attribute that does not include an "id" subtag, the tooltip shows "Entity: entity.". Also, any other attributes being modified by EntityTag are not listed.

Here's an example of a modified creeper egg, for reference: /give @p minecraft:creeper_spawn_egg{display:{Name:'{"text":"Speedy Creeper Spawn Egg"}'},EntityTag:{ExplosionRadius:5b,Fuse:1,Attributes:[{Name:generic.movementSpeed,Base:1.1}]}} 1

Thanks for your feedback! I will wix this Entity: entity thing for sure but I am uncertain about displaying more information as I think it might get a bit crammed then. Might change my mind tho

While it's clearly possible, I've never seen the EntityTag being used to completely change what mob a spawn egg produces. But I have seen instances of other details being modified, so I do hope that you choose to make all custom mob egg data available, even if you put it under a non-default option setting.

Thank you.

I changed it in the new version to show all NBT inside of "EntityTag"

Yes, this is excellent. Thank you very much.