Can someone explain this trigger or point me to documentation. I couldn't find it.
I've inherited several campaigns that use this in their smart list and have the source set to Marketo flow action. I have no idea what this is doing.
What it's doing is a different smart campaign has a flow step included that is sending leads to that smart campaign. The only way the other smart campaign can get the leads is by that campaign is requested trigger. Here's some additional info - Request Campaign - Marketo Docs - Product Docs
So if you're inheriting an instance with these, it'd be good to look through your other active smart campaigns to see which are dependent on each other. Try out the campaign inspector in marketing activities to help.
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