Keep the archive current
Add a list.
Drop in a .conf from ygo.anihelp.co.uk (or anywhere else), or a JSON list in this site's own format. Every passcode gets checked against the card database before anything is saved.
Drop a banlist file
.conf, .lflist.conf or .json. Combined files with several !list sections are fine — you'll pick which one to import.
or paste it
Details
Checks
Publishing saves the list in this browser only, so you can check decks against it right away. To ship it to everyone, download the bundle below and commit it as data/banlists.js.