AFAIK in the (Yarn 0.84) folders, each message is preceded by a
4-byte binary number, Intel style, giving the number of bytes in the
message following. Seek that many bytes from the first character of the
actual message, and you're at the character count for the next message.
This looks a lot like the "Binary 8-bit clean news format" described in
the SOUP documentation, except for the endian-ness of the character
counts.
Regards. Mel.