$ dcrctl --testnet getblockchaininfo | jq -c '.deployments.changesubsidysplit | {status,since}'
{"status":"active","since":877728}
$ dcrctl --testnet getblockchaininfo | jq .deployments.changesubsidysplit.since | dcrctl --testnet getblockhash -
000000000000c7fd75f2234bbff6bb81de3a9ebbd2fdd383ae3dbc6205ffe4ff