commerce-8.x-2.8/modules/promotion/commerce_promotion.links.action.yml

entity.commerce_promotion.add_form:
  route_name: entity.commerce_promotion.add_form
  title: 'Add promotion'
  appears_on:
    - entity.commerce_promotion.collection

entity.commerce_promotion_coupon.add_form:
  route_name: entity.commerce_promotion_coupon.add_form
  title: 'Add coupon'
  appears_on:
    - entity.commerce_promotion_coupon.collection

entity.commerce_promotion_coupon.generate_form:
  route_name: entity.commerce_promotion_coupon.generate_form
  title: 'Generate coupons'
  appears_on:
    - entity.commerce_promotion_coupon.collection