arch-8.x-1.x-dev/modules/product/arch_product.links.menu.yml

entity.product_type.collection:
  title: 'Product types'
  title_context: arch_product
  parent: arch.settings
  description: 'Create and manage fields, forms, and display settings for your products.'
  route_name: entity.product_type.collection
  weight: 100

entity.product.collection:
  title: 'Products'
  title_context: arch_product
  parent: arch.store
  route_name: entity.product.collection
  weight: -10

product.add_page:
  title: 'Add product'
  title_context: arch_product
  route_name: product.add_page