As of today, one can write up to 83 bytes in an OP_RETURN output. This means all data files are fragmented into at most 83 bytes, surrounded by other bitcoin sc

As of today, one can write up to 83 bytes in an OP_RETURN output. This means all data files are fragmented into at most 83 bytes, surrounded by other bitcoin script, sigs and tx input references. They are not sitting around on disk in file form. The blocks also contain things like the EICAR string that will cause AV software to delete block files. To combat this, all bitcoin blocks are obfuscated (encrypted and store the key next to it) with a per node key at rest.