This field is a custom text field that is used to store a special key, by which automated tests and test issues (Test Cases and Test Case Templates) are connected/identified. Automation Test Key is built from a fully qualified class name with a method name.
The Automation Test Key is not presented in the Test Case and Test Case Template by default. If you want to add it to the test issues view, configure appropriate Screen in the Administration > Issues > Screens.
In the image below, the Automation Test Key com.deviniti.jira.plugins.steps.StepsServiceTest.shouldSetStepsComment is composed of:
