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When you move an Epic underneath a Project, the Parent Link will be created on the Epic (after Reviewing Changes).
Dependencies show the relationship between issues in your plan, such as contingencies and blockers.
The following issue link type will be treated as dependencies in plans.
Blocks
Incoming dependency: blocks
Outgoing dependency: is blocked by
Defect
Incoming dependency: defect of
Outgoing dependency: has defects
View dependencies in the Dependencies report tab
Manage your decencies under the Dependency Management view.
Atlassian documentation on documentation