This page sends a "Last-Modified: Yesterday/Now" HTTP response header
Last-Modified: Sat, 08 Aug 2020 13:02:28 GMT
and should respond with 304-Not Modified if you request it (twice) with an "If-Modified-Since: Today/Now" HTTP request header:
If-Modified-Since: Sun, 09 Aug 2020 13:02:28 GMT
(Please read the tutorial, and here is a tool to test Last-Modified/If-Modified-Since/Not-Modified functionality.)
Here is your HTTP request header:
[GET:] /tools/last-modified-yesterday.php?no304=TRUE
[Connection:] close
[Cookie:] tools=www.sebastians-pamphlets.com%2Flinks%2Fcategories%2F%3Fcat%3Dmsn;
[From:] [email protected]
[Host:] sebastians-pamphlets.com
[User-Agent:] ia_archiver
If-modified-since: Thu, 01 Jan 1970 00:00:00 GMT
Last-modified....: Sat, 08 Aug 2020 13:02:28 GMT