Did you read the section on "Relationship to other sequences?"

https://www.superlogical.com/rex/docs/build/program-status#r...

Also - definitely a mention of the terminal bell on https://www.superlogical.com/rex/docs/automate/shell-scripti...

  rex events -s work --json |
  jq -r 'select(.payload.event.payload.name == "bell")
         | .payload.event.payload.block_id'