3.3.1. Lines
The Lines header field indicates the number of lines in the <body>
(as defined in [RFC5322]) of the article.
lines = "Lines:" SP *WSP 1*DIGIT *WSP CRLF
The line count is the number of CRLF separators in the <body>.
Historically, this header field was used by the NNTP [RFC3977]
overview facility, but its use for this purpose is now deprecated.
As a result, this header field is to be regarded as obsolescent, and
it is likely to be removed entirely in a future version of this
standard. All agents SHOULD ignore it and SHOULD NOT generate it.