Unclear documentation

[Yaroslavzev]

In section is said that rake db:clean - removes all tables, but in description of rake-task is said another

  desc 'Perform migration down (erase all data)'
  task clean: :rom_configuration do
    ROM::SQL::RakeSupport.run_migrations(target: 0)
    puts '<= db:clean executed'
  end

What is the intended behavior should be?