Shipment Tracking URL used for tracking your items. Your item’s current location, expected arrival date and more info you can find out from Shipment Tracking number only.
Each Carrier has its specific URL to track items.
Use of sales_quote_address_collect_totals_before events Magento 2.
You can use sales_quote_address_collect_totals_before event for setting your custom totals related data before Magento collect final totals for a quoted address.
Use of address collects totals before event inside observer, You can fetch specific quote data, shipping_assignment, and total related data for a cart.
Use of sales_quote_address_collect_totals_after events Magento 2.
Magento 2 you can use sales quote address collect totals after the event to Collect address total related data after Magento completed the process for a current quote total.
Event Name to used:
sales_quote_address_collect_totals_after
Using the above event in the observer, you can fetch specific quote data, shipping_assignment, and total related data for a cart.