You can check the shipment comments by Magento 2 using Shipment Comment Repository Interface with shipment id.
How to Get all active Catalog Rules collection Magento 2?
Magento 2 You can retrieve the active catalog rules of the system. Using Active rules, You can identify a number of rules that are active and working for the catalog category pages.
To identify, an active rule you need to filter the catalog collection by is_active field. Value 1 contains the active and 0 used to disable the rule in the system.
How to Set Product final price using catalog_product_get_final_price Event in Magento 2.
You can modify the final price value by define events in your XML file with Magento 2.
catalog_product_get_final_price the event defined under the Magento\Catalog\Model\Product\Type\Price class.
You can also interested to check, A Complete List of all events in Magento 2.