Complex sentence: The only exceptions to this rule are regulated in the Secrecy Act (Sekretesslag 1980:100), detailing what government agencies can keep secret what type of document, under what circumstances, and towards whom.
Split into simpler sentences: The only exceptions to this rule are regulated in the Secrecy Act (Sekretesslag 1980:100). The exceptions that are set out in the Secrecy Act are detailed and state at what government agency what type of document can be kept secret, under what circumstances, and towards whom.