To help troubleshoot and respond to actions in checkout, the developer's code should listen for CommerceDiagnosticEvents. CommerceDiagnosticEvents is an event that is fired by Salesforce B2B Commerce when an error occurs in the storefront. CommerceDiagnosticEvents contains information about the error, such as error code, error message, error type, and error details. CommerceDiagnosticEvents can be subscribed by other components or services that want to handle or display the error information in different ways. The developer's code can listen for CommerceDiagnosticEvents using an aura:handler tag in Aura Components or an @wire decorator in Lightning web components. The developer's code can also use the event information to perform custom logic or actions based on the error, such as logging, reporting, or notifying. CommerceBubbleEvents is not an event that the developer's code should listen for in checkout, as it is not related to troubleshooting or responding to actions. CommerceBubbleEvents is an event that is fired by Salesforce B2B Commerce when a user interacts with a bubble component in the storefront. A bubble component is a user interface element that displays information or options in a pop-up window when clicked or hovered over. CommerceBubbleEvents contains information about the user interaction, such as bubble name, bubble type, and bubble value. CommerceErrorEvents is not an event that the developer's code should listen for in checkout either, as it is not related to troubleshooting or responding to actions.
CommerceErrorEvents is an event that is fired by Salesforce B2B Commerce when a validation error occurs in the storefront. CommerceErrorEvents contains information about the validation error, such as field name, field label, and error message. CommerceActionEvents is not an event that the developer's code should listen for in checkout either, as it is not related to troubleshooting or responding to actions. CommerceActionEvents is an event that is fired by Salesforce B2B Commerce when a user performs an action in the storefront.
CommerceActionEvents contains information about the user action, such as action name, action type, and action parameters. Salesforce References: B2B Commerce Developer Guide: Handle Errors, B2B Commerce Developer Guide: Handle User Interactions with Bubble Components, B2B Commerce Developer Guide:
Handle Validation Errors, B2B Commerce Developer Guide: Handle User Actions

Mass Order pricing is done via a batch job, which means that the prices are not calculated in real time, but rather at a scheduled time. Mass order works with the variation product, which is a product that has multiple SKUs with different attributes, such as size or color. Mass order does not work with the default wishlists, which are used to store products that the customer wants to buy later. Mass order is not mobile ready with the ccrz templates, which are the default templates for the storefront pages. Salesforce References: B2B Commerce Developer Guide: Mass Order, B2B Commerce Developer Guide: Variation Products

A valid way of referencing the CC Cart Object whose API name is E_Cart__c in a SOQL query is to use ccrz__E_Cart__c. This is the transformed name of the object that is used by the Salesforce B2B Commerce framework. All custom objects and fields that are part of the cloudcraze managed package have the prefix ccrz__ in their API names. For example, SELECT Id, Name FROM ccrz__E_Cart__c will query the CC Cart Object records. Salesforce Reference: B2B Commerce and D2C Commerce Developer Guide, Query Transformation

To retrieve metadata about a specific object, a developer should use the getObjectInfo wire adapter. The getObjectInfo wire adapter imports data from the @salesforce/schema module and returns an object that contains information such as the object's label, key prefix, fields, child relationships, record type infos, and theme. The getObjectMetadata wire adapter does not exist. The getObject wire adapter does not retrieve metadata, but rather returns a record object based on the record ID. The getObjectDescribe wire adapter does not exist either. Salesforce Reference: [Lightning Web Components Developer Guide: getObjectInfo], [Lightning Web Components Developer Guide: Import Salesforce Schema]

Three steps that are necessary to have a subscriber page added to Salesforce B2B Commerce after creating a custom Visualforce page are:
Create a new CC Subscriber Page record that points to your custom Visualforce page. This record will store information about the subscriber page, such as the name, description, URL, and Visualforce page. For example, you can create a new record named MySubscriberPage that points to your custom Visualforce page named MyPage.
Refresh the Page Keys Index in CC Admin. This action will update the page keys index, which is a cache that stores the mapping between the page keys and the subscriber pages. You need to do this whenever you create or modify a subscriber page record.
Enable the Subscriber Page in CC Admin. This action will allow you to select the subscriber page from the CC Page Settings configuration and assign it to a CC Page. For example, you can enable MySubscriberPage and assign it to the Home page. Salesforce Reference: B2B Commerce and D2C Commerce Developer Guide, Subscriber Pages