Could someone from pgsql-www add it, or let me know who to contact?
Just to note, I’m not on the organizing team, so I don’t have the description text.
That's an archive of the events that were submitted as event listings prior to their occurrence, at https://www.postgresql.org/about/events/ (with a summary on the homepage). If a conference isn't listed there, it won't be included in the archive.
Whilst technically we could add it now, I don't think we should, as that would defeat its purpose as an archive of old listings.