To provide a single tag to advertisers, that acts like a master tag and provides capabilities to tag everything on site with this single tag. This tag provides for integration of multiple campaigns, multiple campaign types as well as different services, like re-targeting etc. via a single tag, with zero dependency on changes on the advertiser side, post initial deployment.
Following two combine to make one set of tags to fire.
In the container pixel variables are passed in JSON format. The text marked in upper case is the variable name and the text in lower case is the value that would be passed by the advertiser.
If you are using container for a lead campaign then the variable name would be LEADID_VALUE. You can pass the lead id in it as shown below.
TRANSACTIONID_VALUE, ACTIONKEY_VALUE, CARTVALUE_VALUE are the variables and their values should be passed. Transaction id is mandatory for CPS campaign.