Tagged files are too useful. 4 byte tag name, 4 byte length of the object, then the binary data of the object. You see these all the time. Sometimes you see

Tagged files are too useful. 4 byte tag name, 4 byte length of the object, then the binary data of the object. You see these all the time. Sometimes you see the size before the tag name. Occasionally, you also see a file header, followed by a size, and an "x", that often indicates a block of ZLIB compressed data.