Meta: I didnt see an explicit date on the page and am ballparking 1999 because the <meta> GENERATOR tag says Netscape 4.51: <https://en.wikipedia.org/wiki/Netscape_(web_browser)#Release...>
WA has the earliest snapshot at April 9, 2001 https://web.archive.org/web/20010409214430/https://www.doom2...
https://www.doom2.net/doom2/sr50.html says: If you downloaded the lmpdet utility prior to April 8, 2001, we suggest you download it again to pick up a new version of the documentation textfile within the zip.
https://www.doom2.net/doom2/autoaim.html has a demo from 1997.