The phrase is a mash of two words from the mid-2000s screen era. Frutiger is the humanist sans that ran the interface, the soft, slightly rounded letterform that made the Vista window look warm instead of sterile, and Aero is the Vista word for the glass, the translucent panel that let the desktop bleed through. Put the two together and you have a specific visual language: the soft aurora gradient, the water droplet beading on the glass, the leaf pressing up through the bottom corner, and the light refraction that makes the whole thing read as behind a surface instead of on one.
For a decade the style was so constant it was invisible. The glossy button, the bubble, the foliage, the dawn blue rolling into the misty green, it was the wallpaper behind the icon, the default state of the interface before the flat-design turn made everything look like paper. The moment that turn happened, the language went into nostalgia the way a piece of furniture does, still real, just no longer in the room. That is where the second word lands.
Yams is the slang layer, the word the feed uses for the thing that is all glaze and nothing under it, the glossy wrapper with an empty plate. Apply it to the aesthetic and you get the running joke of the comeback, the frame that posts the shine and the glass effect and none of the substance, the tag attached to an image that does not actually do what the style does. The detector is built on that exact split, the frames that breathe against the frames that just glaze, and the card grades which side of the split the eye lands on.