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Where the receipt of a cross-context command goes when the target rejects it: the receipts topic of context, the sender's, and the saga handler subscription (processor.function) whose execution of the commit ref@version derived it, the executionId the saga's @OnRejected handler gets. The design's {context, subscription} carries the commit too, so the receipt names the execution exactly.

committed (an addition within format 1) asks for the success receipt too: the saga has an @OnCommitted handler of the command, so the target sends the receipt of its commit there as well. A reader of an older version ignores it and sends none; one reading an older writer's reply has it false.