Returns child issues (on Portfolio hierarchy) of issues specified by the provided subquery. See also: portfolioParentOf()
Note: Since you need to enclose the provided subquery using doble quotes, you must to escape any doble quotes using in the subquery by preceding a backslash after the double quotes, alternatively you can use a single quote in some cases.
This function does not traverse the link from Epic to Story. To also search for stories, or subtasks you should use this function in conjuntion with issuesInEpics() or subtasksOf() JQL functions.