Smart Identifier

Smart Identifier

How do I find the "Smart Identifier"? It seems the following description is obsolete:

To include the smart identifiers code to the email, select the campaign name from the “Choose a campaign” drop down of Smart Identifiers in the Web Embed section. A Campaign specific code will be provided in the Smart Identifier Code box. Attach the code to the email, when the recipient opens the email the smart identifiers will track the identity.