just a simple hint...

Show the mail header.

When you are vieweing the folder index,
type 'h' which is bound to the command 'display-toggle-weed'.
this will toggle the option "weed" and then
change to the pager and show you the message.
If the value of the option "weed" is "no" then
you will see the message with its full header;
otherwise (weed=yes) the header will be shown
after it has been weeded from unwanted lines.
Use the setup commands "ignore" and "unignore"
to select which headers should be selected.
Note that "weed" also applies to commands
that forward, print and reply to emails.

h       display-toggle-weed     display message and toggle header weeding