Start an issue with "From " and submit it via the email interface.  It
seems that roundup will just delete that line altogether.

We speculate that this is due to an interaction between some
From-stuffing mechanism and the email-trimmer mechanism.  By
from-stuffing we mean the fact that the "From " line will get converted
to "> From " somewhere along the way.  By email-trimming, we mean the
things that happen when thing that happens when leave_body_unchanged is
unset.

The From stuffing is fine.  It's just the email trimming which is
worrying.  Maybe it needs to be made less aggressive and only cut out
things that look like signatures.  Otherwise you get data loss, with
content that only looks like a quote but isn't getting cut out.

For more details, see
- http://bugs.darcs.net/issue1667 and also
- http://bugs.darcs.net/issue1596