headerlabelalign keyword controls the alignment point
for message headers enqueued on this channel; it takes an
integer-valued argument. The alignment point is the margin where the
contents of headers are aligned. For example, sample headers with an
alignment point of 10 would appear as follows:
To: email@example.com From: firstname.lastname@example.org Subject: Alignment test
headerlabelalignis 0, which causes headers not to be aligned.
headerlinelength keyword controls the length of
message header lines enqueued on this channel. The default, if this
keyword is not explicitly set, is 80. Lines longer than this are folded
in accordance with RFC 822 folding rules.
Note that these keywords only control the format of the headers of the message in the message queue; the actual display of headers is normally controlled by the user agent. In addition, headers are routinely reformatted as they are transported across the Internet, so these keywords may have no visible effect even when used in conjunction with simple user agents that do not reformat message headers.