> when I was playing with reading gmail with acme/Mail I sent a simple
> e-mail to my gmail acount (from some webish outlook program, if that's
> important), but then I saw this in the body of email as shown in acme
>
> 9p read mail/mbox/1375/body > //a
>
> can anybody tell me what it is?

acme mail thinks it is an attachment,
so it is telling you that you can get the
content by running that command.
usually the file name looks nicer.