bat-8.x-1.x-dev/modules/bat_booking/bat_booking.links.menu.yml

entity.bat.booking:
  title: 'Booking'
  route_name: bat.admin.booking
  description: 'Booking settings'
  parent: bat.admin
  weight: 600

entity.bat_booking.collection:
  title: 'Bookings list'
  route_name: entity.bat_booking.collection
  description: 'List Bookings'
  parent: entity.bat.booking
  weight: 601

entity.bat_booking_bundle.collection:
  title: 'Booking Bundles list'
  route_name: entity.bat_booking_bundle.collection
  description: 'List Booking Bundles'
  parent: entity.bat.booking
  weight: 602