Central to the idea of the smart government is (near) real-time access to detailed ledger transactions or aggregated ledger reports.
The relationships between the ERP-application, accounting function and ledger services are just basic definitions of services and interfaces without many assumptions being made.
The diagram shows an accountant role providing an accounting-service to the SME through the accounting-function of an ERP-system. The SME might do the accounting inhouse, but with increased requirements for integration across enterprises and public agencies it seems reasonable to assume that a decreasing number of companies will choose this option.
Also, with increased integration of structured data across the entire value chain, the need for an accountant role might vanish completely. The need for external audit will probably still be needed, but with increased integration and automation, it might be replaced by automatic audits by government agencies such as tax authorities.
The external stakeholders are mostly from the stakeholder analysis. Neither this nor the business case are specific on which use cases are considered or which data the different stakeholders might be interrested in, but the connections in the model list some assumed use-cases which seem reasonable. Please also see the "analysis" and "credit lending" views for more stakeholder relationships.
There is a distinction between the services "ledger details" and "ledger aggregation" to be able to show which stakeholders would have access to which level of detail. The business itself will probably want to control which stakeholders have access to which details. A typical example would be that media would probably like to have access to all details, while the business only want to show aggregated reports.
The ledger details might also reveal personally identifiable information, especially when correlated with other sources. So the privacy implications of these services needs to be considered carefully and appropriate access control needs to be implemented.