As per the docs you should be able to get issue.getParent() to get the parent object. From this object you should be able to get the data from parent and add to the email content.
And this link also may be helpful. Do appropriate condition checks so that the template works for non sub-tasks items too.
I’m a designer on the Jira team. For a long time, I’ve fielded questions from other designers about how they should be using Jira Software with their design team. I’ve also heard feedback from other ...
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