Looking at the documentation it implies that the (a) Salesforce Connector can used to talk to Marketing Cloud/Exact Target.
Pre-built Connectors. Boomi provides pre-built connectors to common Salesforce endpoints, such as Sales Cloud, Service Cloud, Force.com, Analytics Cloud, Platform Events, and more.
This process isn't obvious, and I was unable to get it to work.
Is there any documentation on the process to use Pre-built Connector for Marketing Cloud?
(If not, I'll import the WSDL's and do it that way.)