This is a wanikani example sentence, and I posted about it on their community tab, but users here tend to have a much better grasp on linguistics etc, so I will ask here.
How is the grammar functioning here, じゃない is used for “are not for”. Any breakdowns and or further examples of how じゃない is functioning and why? I haven't seen it used like this before (I've only recently started reading more in Japanese) but I would like to drill this into my head so I won't be confused whilst reading if it comes up more.