commerce-8.x-2.8/modules/product/commerce_product.links.action.yml

entity.commerce_product.add_page:
  route_name: entity.commerce_product.add_page
  title: 'Add product'
  appears_on:
    - entity.commerce_product.collection

entity.commerce_product_attribute.add_form:
  route_name: entity.commerce_product_attribute.add_form
  title: 'Add product attribute'
  appears_on:
    - entity.commerce_product_attribute.collection

entity.commerce_product_type.add_form:
  route_name: entity.commerce_product_type.add_form
  title: 'Add product type'
  appears_on:
    - entity.commerce_product_type.collection

entity.commerce_product_variation_type.add_form:
  route_name: entity.commerce_product_variation_type.add_form
  title: 'Add product variation type'
  appears_on:
    - entity.commerce_product_variation_type.collection