Extraído de "About Freenet" e os itens em negrito são citados e sua resposta é:
Users contribute to the network by giving bandwidth and a portion of their hard drive (called the "data store") for storing files. Files are automatically kept or deleted depending on how popular they are, with the least popular being discarded to make way for newer or more popular content. Files are encrypted, so generally the user cannot easily discover what is in his datastore, and hopefully can't be held accountable for it. Chat forums, websites, and search functionality, are all built on top of this distributed data store.
Extraído do link
É claro que você sempre pode tentar descriptografar esses arquivos. Existia em algum lugar no seu computador. Boa sorte para decifrá-los.