Key legal question
Whether the federal appeal was admissible against the cantonal summary order.
Extracted holding
The summary child-return order was treated as a final decision in a non-monetary civil dispute, so the appeal was admissible in principle.
Extracted reasoning
A meritorious order in the Zurich befehlsverfahren has res judicata effect and final character; a later change of residence of a party after the cantonal decision did not affect federal jurisdiction.