There are Maine Coon breeders on here that get angry when you ask questions about their pedigree. Any good breeder will supply you with that information and not get angry with you when you ask.
Please also watch when you are looking, as people are posting different kittens in different areas and it is the same person.
If someone is selling a kitten and you are not able to register the kitten for an additional fee are not true breeders. True breeders take pride in their kittens, and they are just not a source of income.