https://www.theverge.com/2018/12/11/18135751/doom-sigil-the-ultimate-doom-5th-episode-mod-john-romero
https://techcrunch.com/2018/12/10/doom-is-25-and-co-creator-john-romero-is-putting-out-a-giant-expansion-for-it/
origin - https://www.pipiscrew.com/?p=14497 doom-is-getting-a-25th-anniversary-mod-from-the-games-co-creator