Can you provide some architectural details about BBBi?

BBBi resides within your E-Business Suite database. It includes tables, views, database functions, procedures, and triggers. At the core is a layer of PL/SQL code that dynamically generates the database objects required to interpret Oracle transactions and configurations, and to output the translated data via views, reports, and forms for presentation to the user. BBBi is registered as an Application within the Application Object Library.

ProView is delivered as an Oracle Application Express application, with an optional BBBi module.  ProView for BBBi includes a set of browser pages for interactive reporting.