· -e / --exit-status:
Sets the exit status of jq to 0 if the last output values was neither false nor null,
1 if the last output value was either false or null, or 4 if no valid result was ever
produced. Normally jq exits with 2 if there was any usage problem or system error, 3
if there was a jq program compile error, or 0 if the jq program ran.
From
jq
manpage: