Depending on the request, the response will be returned with base64 encoding. You would need to parse the response from the gateway and then decode it.
For example - Using mgmt_cli on the Manager and running ifconfig on the gateway and filtering for the task details:
# mgmt_cli -r true run-script script-name test2 script "ifconfig eth1" targets gw01 -f json | jq -r '.tasks[]|."task-details"[]|.responseMessage'| base64 -d
It provides the following data:
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Time: [15:02:13] 9/12/2019
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"gw01 - test2" succeeded (100%)
eth1 Link encap:Ethernet HWaddr 00:1C:7F:84:6B:68
inet addr:172.16.99.1 Bcast:172.16.99.255 Mask:255.255.255.0
inet6 addr: fe80::21c:7fff:fe84:6b68/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:108809061 errors:0 dropped:10061860 overruns:0 frame:0
TX packets:315274900 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:27556684726 (25.6 GiB) TX bytes:443734405363 (413.2 GiB)