In <news:quodnriz-z8s5chonz2dnuvz_r-dn...@mozilla.org>, "David E. Ross" <nobody@nowhere.invalid> wrote:
> For newsgroup messages, the User-Agent header field is indicated in > RFC 5536 as optional. For E-mail messages, the User-Agent header > field is not even mentioned. All header fields beginning with X- > (e.g., X-Mailer) are non-conventional. I strongly doubt that > Thunderbird recognizes X-Mailer (or any other similar header field) > as a substitute for User-Agent. The convention of using the prefix 'X-' for non-standard headers has been in use a long time. The prefix wasn't strictly necessary, but it pretty much guaranteed that no future RFC would clobber such a header by redefining it. (Non-standard headers without the prefix were/are used too, of course.) Until 5536 obsoleted 1036 for netnews, there was no standard header to indicate what client composed the message in either news or e-mail posts. All there was was the informational RFC 2076, which listed these headers in common use for it in 1997: Mail-System-Version Mailer Originating-Client X-Mailer X-Newsreader So Mozilla products should recognize at least those. (I don't know whether they do or not.) I don't know what Netscape 3's mail/news used. It was released only shortly before RFC 2076 was put out. At some point, either Netscape or Mozilla decided to use the HTTP header "User-Agent" instead of what other message clients were using. Eventually "User-Agent" made its way into RFC 5536 as the standard one to use for news. This giant cross-posted thread wouldn't exist if Mozilla products just let users pick which headers are visible in the normal header view, something like <http://remarqs.net/misc/header-display-config.png>. I've set followups to m.s.seamonkey. _______________________________________________ support-seamonkey mailing list support-seamonkey@lists.mozilla.org https://lists.mozilla.org/listinfo/support-seamonkey
