This user parameter has been configured on Zabbix server

The script sme_slack_etl.py calls bash script sme_slack.sh which uses Slack API to get messages from channel for particular period of time and store it in tmp file /tmp/slack.json
Next in sme_slack_etl.py that temp file is parsing to get number of messages and messages which contain key:value - JobFailed:true.
If it find such key:value script returns 1 and returns 0 in other case