She was given custody of the children by the judge. OR: It was her whom the judge gave the children.
The -iko- element indicates that the obviative NP marked with -a is the subject. It is an inverse sentence, and the order is: recipient - theme - verb - agent. The agent is marked as obviative, and the recipient is grammatical subject. The original is not a passive sentence, but one in which the topic (she/her) is unmarked and the new noun phrase (judge) is marked with an obviative marker -wa. The obviative marker is not always overtly expressed.