http://3cbzkrvakrpetjjppdwzbzqrlkmzatjs7jbyazap5gwutj32gcltjpqd.onion
Most textures are paletted to save VRAM (so instead of 555+1, your
pixels now mean something like “two palette indexes”). Where does the palette live? Well, duh, that's a 256x1 (or 16x1, or whatever) area of VRAM too.
The GPU does not care, you can use another texture's pixels as a palette if
you feel like it.