Why can we only learn about 53 thousand names from the data of the super-secret magnetic tapes of the Kádár state security?

This week, names of individuals recorded by the Kádár regime's state security will be made public, but the lists are incomplete. Estimates suggest around 150,000 to 200,000 agents were recruited, yet only 24,000 records exist in the Historical Archives of State Security Services. Approximately 53,000 names will be released from magnetic tapes, with overlaps expected with the existing records. However, data on intelligence agents remains inaccessible. A report from 2017 revealed about 58,000 names on a specific magnetic tape, with around 3,000 not being agents. The upcoming public list will not include these names. Despite political will, the extensive document destruction post-regime change complicates transparency.