🚀 go-pugleaf

I do not have a Next, but someone I know mails me messages with 
embedding things like sounds, pictures, and formatted text.  When I 
look at the raw mail files, they look exactly like uuencoded binaries.

>Subject: jpeg FAQ
>Next-Attachment: .tar.148.jpeg_FAQ.attach, 32831, 1/1, 45144, 0
>Status: OR
>
>begin 666 .tar.148.jpeg_FAQ.attach
>M'YV0:=R0*8/'A1PZ9@`H7,BPH<.'$"-*G$BQ(HB+-FC0``'@XD4:,3AZ!"%C
>M8\>1,6;8L'%#QL4:,V#(F`'S!HP9%V/(D'FC(XR*0(,*'4KT89TY=,+(N0C@
>M:!DV;<*X<5.TX1LZ:,K(J<JUJ]>O8,.*[;J'RT$S,+A(G9.FK)DW;NC0$<.&so

So, the first thing I do is uudecode them.  This usually results in a file 
with a name like

>.tar.148.jpeg_FAQ.attach

Then, I proceed to assume that this is a tar archive of all the embedded 
objects, so I run this into tar to look at the list of files using syntax 
like:

tar -tf .tar.148.jpeg_FAQ.attach

This always gives me a table of contents error, or a "hmmm, this 
doesn't look like a tar file to me" error on the Next.

I believe the first part was right, uudecoding the message, but what 
should I do with this binary file that comes out of it, that seems like it 
should be an ordinary tarfile, but isn't?  Is this in some proprietary 
Next format, or are the technical details about this publicly accessible 
somewhere?  I am a programmer, and would not mind writing a simple 
app for other computers to decrypt Next mail messages, but I have to 
know where to start.

If anyone has any insight into this, please let me know, or tell me what 
publications to look at.

Thanks - Tom