Implementing custom commands for ReactiveMongo 1.x.x

Question

In the commands.scala file here of the ReactiveMongo Github repo, we are seeing the following :

trait Command {
  private[reactivemongo] def commandKind: CommandKind
}

This is a clear difference from previousl releases (0.20.x and earlier).

By changing this trait, one is making the implementation of a def named commandKind mandatory for any custom command implementation.

Does this mean that going forward implementing a custom ReactiveMongo command must always be done by introducing the package [reactivemongo] into our own projects ?

This is rather confusing, as that requirement appears to be absent in the examples given here