You might be
interested in using kshowmail sometimes (i.e.,
kshowmail-trinity). Use kshowmail to preview only email headers;
but you can also click to read plaintext versions of selected items.
Bill
Sorry, me again.
kshowmail-trinity does'nt seem to exist,
and also kshowmail (I'm on Stretch).
However, kshowmail exists for KDE.
Thanks,
André