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The rule above is named send_twilio_sms_message but selects when the pico receives the twilio:new_sms_message event. The name is solely for reference (in logs for example) and must be unique in within a ruleset. The select when clause is part of the declaration of what events are salient for this rule (or, as we say, for which the rule selects). Incidentally, notice that rule names are typically verbs which while event names are usually nouns.
A common mistake would be to use this the code below (perhaps in some other ruleset) to trigger the send_twilio_sms_message rule:
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