NEED TO LOCATE PLSQL_FUNCTION_NAME OR EQUIVALENT DETAILS FOR XLA_SOURCES_B

Standard functionality in Subledger Accounting is to be able to create custom sources to derive specific data. I have done such and when I test the source it returns data, however when i utilize it in an account derivation rule in Receivables Subledger Accounting it returns an error that no data is found. I need to know what package, function and/or database location where these details exist so that I can understand the plsql_function_name or equivalent that would be assigned to the seeded source to understand how there are deriving the return details in XLA_SOURCES_B. For instance, running the sql