Data Migration & Onboarding — Moves an acquired or migrating customer's subscriptions, balances, and usage history into the new billing system without breaking their invoices. It seeds asset records and open balances that rating and AR then treat as native.
Data Migration & Onboarding lives in the Fulfill & Activate phase of Fulfill & Bill — the stage where you activate what was sold, meter what's used, bill it right. In the corpus tool index this phase maps to the Entitlements and Billingcategories.
No product category maps cleanly onto this module yet — companies typically build it in-house or cover it with adjacent tooling. See who builds vs buys across the corpus.