Use case

This calculated field returns the last comment, its author, and timestamp in a text field.

Configuration

Create a new Calculated Text Field (by JWT) custom field and name it properly.

Providing a description will help you to identify what the custom field does but this step is optional

Select Advanced text as parsing mode.

Add the following expression:

to do

Add the field to the relevant view screens.

Remember: All calculated fields are read-only and cannot be manually updated on a create or edit screen.

Check the results

Once configured and added to an issue screen, the result will look like this:

SCREENSHOT