ITT we post everything we have and know about 4chan's moderation and how the site works in general.
I'll split the OP into several two or more posts, in each one dumping info and links.
Firt off, simple hidden pages:
>https://boards.4channel.org/test/Hidden board. Can't be accessed and it's unknown how it looks like.
>https://boards.4channel.org/j/Janny board. Can't be accessed right now but it was breached earlier. Stick around if you wanna see an archive of it from 2006 to 2014. Rumored to be inactive and used as a shitposting ground for jannies.
>https://a.4cdn.org/boards.jsonA list of boards and their specifications, including cooldowns, bump limits, image limits and whether if webms can have audio.
>https://www.4chan.org/securityDon't do what this page tells you. All you get is your name put on a list that almost nobody will see since the page is hidden.
>https://www.4chan.org/sitemap.xmlI'm using this more as a post shorterner. This link has all the other hidden links that I didn't post here. Nothing special, just old contests and shit like that.