WALL takes the mood straight, through a link or a live apply. FX wears the look as a layer, once fx.js is on that site. A site without the script shows nothing — the badge is what it can do, not a promise that it is installed.
Rate stays inside 0.07–1.4 Hz and depth caps at 16%, well clear of the 3–60 Hz band that triggers photosensitive seizures. Reduced-motion settings switch the pulse off entirely. The push endpoint clamps the same range again, so nothing outside it can reach a site.