https://confluence.atlassian.com/display/ADMINJIRASERVER/Importing+data+from+JSON

It would be helpful to clarify that if you're trying to create sub-tasks for custom sub-tasks links you need to keep the name "sub-taks-links"

The example shows this but it's a little confusing and if you change the name things get really weird.

i.e.

 "links": [
        {
            "name": "sub-task-link",
            "sourceId": "2",
            "destinationId": "1"