I take back what I said about my stupidly obtuse secret in BA2 being easier to discover than this. It absolutely isn't, but I was so overwhelmed by the bullshittery of this secret that I wasn't really capable of making a fair comparison. Mine is still worse, but this one is pretty bad anyway. After a quick google search, I did find that CastChaos basically intended this as an easter egg (as I suspected) and an excuse to put every item somewhere in the game. I'm also now worried that I've kind of ruined the ending for myself by doing this, but I'm not sure how much I actually care.