Salesforce User Integration- Ability to customize?

Summary:

We would like to understand how the user integration works between Salesforce.com and Oracle CPQ. We are on Managed Package 8. We are trying to understand how the fields are mapped between the systems with the ultimate goal being to customize that integration and add a new field. Oracle support suggested we contact this community to get the details on how the integration works and whether it can be customized.

Content (please ensure you mask any confidential information):

How does the User integration work between Salesforce and Oracle CPQ and can it be customized to add a new field?