Finding and your answer
Account.AccountType column
Direct match
98%
How the model read it
Current gold observes the exact String Account.AccountType column. Structural coverage is direct, although the register definition mentions revenue/expense while the fictional examples also include asset, liability and equity values.
Workbook evidence
Cited current gold
Open questions
Should AccountType cover the full balance-sheet and P&L domain (Asset, Liability, Equity, Revenue, Expense), rather than only the register's stated revenue-or-expense classification?