To see what scripts, reports, and other application artifacts will be in a published application, the best option is to examine the Application Files Related List in the application to be published. This will show all the application files that belong to the application, grouped by file type and scope. You can also filter, sort, or search the list to find specific files.
The following options are not the best ways to see what application artifacts will be in a published application:
Enter the name of the Application in the Global search field. This will perform a global text search on the instance and return any records that match the application name, which may include irrelevant or incomplete results.
Open the list of Update Sets for the instance. This will show all the update sets that have been created or imported on the instance, but not necessarily the ones that belong to the application to be published. Update sets are used to move customizations between instances, not to publish applications to the ServiceNow Store or Share.
Open the artifact records individually to verify the value in the Application field. This will require opening each record that may be part of the application and checking the Application field, which is tedious and error-prone. References: Publish an Application, Application Files

The ServiceNow REST API is a web service that allows you to interact with the ServiceNow platform using HTTP requests and responses. The ServiceNow REST API supports the following methods:
POST: This method allows you to create a new record or execute an action on the ServiceNow platform. For example, you can use the POST method to create an incident or run a script.
GET: This method allows you to retrieve information from the ServiceNow platform. For example, you can use the GET method to get the details of a user or a table.
DELETE: This method allows you to delete a record or a resource from the ServiceNow platform. For example, you can use the DELETE method to delete an attachment or a workflow context.
PUT: This method allows you to update a record or a resource on the ServiceNow platform. For example, you can use the PUT method to update the state of a task or the value of a system property.
PATCH: This method allows you to update a record or a resource on the ServiceNow platform by sending only the changes. For example, you can use the PATCH method to update the short description of an incident or the order of a module.
The method COPY is not part of the ServiceNow REST API. There is no COPY method in the HTTP protocol. To copy a record or a resource on the ServiceNow platform, you need to use the POST method with the clone action.
References:
ServiceNow REST API overview
ServiceNow REST API methods
[ServiceNow REST API actions]

Inbound Action scripts are server-side scripts that run when an email is received by the system. They can use the current object to access the record that is created or updated by the email, and the email object to access the properties and methods of the email message. The previous and event objects are not available in Inbound Action scripts. The producer object is only available in Record Producer scripts, which are used to create records from a service catalog item.
References:
Inbound Action scripts
[Record Producer scripts]

One of the uses of the ServiceNow REST API Explorer is to create sample code for sending REST requests to ServiceNow. The REST API Explorer is a tool that allows you to discover and test the ServiceNow REST APIs. You can select an API endpoint, set the HTTP method, parameters, headers, and body, and then execute the request. The REST API Explorer will show you the response status, headers, and body, as well as generate sample code for various languages and frameworks, such as cURL, Java, JavaScript, Node.js, Python, Ruby, and more. References: [Use the REST API Explorer - Product Documentation: Tokyo - ServiceNow], [Introduction to Scripted REST APIs - ServiceNow Developers]

The fastest way to create and configure a Record Producer is to open the table in the Table records and select the Add to Service Catalog Related Link. This will automatically create a Record Producer with the same fields as the table and add it to the Service Catalog. You can then modify the Record Producer as needed. The other options require more steps and manual configuration. Reference: Create a record producer