Thanks to you mentioning this, I checked again and I figured it out! Hint (use rot13 to decipher): gurer'f n cnggrea va juvpu gb ernq gur yrggref ba gur yrsg cntr.
If you can't find it: ybbx sbe n snzvyvne frdhrapr bs yrggref.
If you're sure you solved it but it doesn't work: hfr pncf ybpx.
I hadn't noticed the clover, but I notice that the game's symbol looks a lot like a clover... I wonder what's up with that. I wonder if the clover lore points to something else in the Kultisi-verse. This game still might have secrets. I haven't unlocked all palettes, so I wonder if it would cause something else to appear. When did that book appear anyway ? Was it after the "canvas" puzzle ?