You are entitled to information from the government. This is specified in the Wet open overheid (Woo, the 'Open Government Act'). You can look into anything the government does, unless the Woo or an other law determines that something is unfit for publication.
DUO is part of the Dutch government. DUO gives information about what it does. And what rules it complies with. For instance in press releases (in Dutch) or the open data on education (in Dutch).
If you want to know more, you can ask DUO to send you specific information. This is called a Woo request. More information (in Dutch) on Woo requests.