Summary / TL:DR: WMC sends this event to Blueshift when a customer lands on an order form page and to streamline abandon campaigns.
...
Purpose
To indicate in Blueshift when a customer has viewed an order form. This event will also be used in abandon campaigns to qualify users for abandon campaigns.
...
Description
When a customer lands on an order form page, WMC will fire this event to Blueshift and will get recorded to both known and unknown user profiles. The vid2 parameter which includes the encrypted email address is included in all links sent from Blueshift which WMC decrypts to include it in the event payload. This allows the event to get recorded to the known user profile associated with that email. This event payload will always include the email address from the vid2 value. If an anonymous user lands on an order form the event will be sent with just the cookie that comes from the integrated pageload script that fires on all WMC pages.
...