How the new relationships in SwiftData work?

There is a new Relationship macro in Xcode Beta 6. The macro includes two new arguments: minimumModelCount and maximumModelCount. I wonder if anyone knows what these values are for and if there is another change under the hood.

Relationship(
    _ options: PropertyOptions...,
    deleteRule: Schema.Relationship.DeleteRule = .nullify,
    minimumModelCount: Int? = 0,
    maximumModelCount: Int? = 0,
    originalName: String? = nil,
    inverse: AnyKeyPath? = nil,
    hashModifier: String? = nil
)