mh-scan-format-mh

mh-scan-format-mh is a variable defined in `mh-scan.el'.
Its value is

"%4(msg)%<(cur)+%| %>%<{replied}-%?(nonnull(comp{to}))%<(mymbox{to})t%>%?(nonnull(comp{cc}))%<(mymbox{cc})c%>%?(nonnull(comp{bcc}))%<(mymbox{bcc})b%>%?(nonnull(comp{newsgroups}))n%>%<(zero) %>%02(mon{date})/%02(mday{date})%<{date} %|*%>%<(mymbox{from})%<{to}To:%14(friendly{to})%>%>%<(zero)%17(friendly{from})%>  %{subject}%<{body}<<%{body}%>"

Documentation:
*Scan format string for MH.
This string is passed to the scan program via the -format
argument. This format is identical to the default except that
additional hints for fontification have been added to the fifth
column (remember that in Emacs, the first column is 0).

The values of the fifth column, in priority order, are: "-" if
the message has been replied to, t if an address on the To: line
matches one of the mailboxes of the current user, "c" if the Cc:
line matches, "b" if the Bcc: line matches, and "n" if a
non-empty Newsgroups: header is present.