Shown in Report

Arrr, matey, shiver me timbers! There be buried treasure herrrrre.
Just kidding, I'm not really a pirate, I was just hoping it would make finding the treasure easier.
I guess you heard about the fabled buried treasure, too? I didn't expect to see anyone else here. This uncharted islet was hard to find.
There are 3 buried treasures in total, each in its own uncharted area around Geese Islands.
I've been searching for hours now with no luck, and these strange toys are starting to give me the creeps.
Maybe you'll be able to find it. Here, use my Gameboy Cartridge Detector. Go into your items and test it to make sure it's still working.
When you get close to the treasure, it'll start sounding off. The closer you get, the louder the sound.
No need to activate or fiddle with it. It just works!
I bet one of these creepy toys has the treasure, and I'm sure not going anywhere near them!
If you find the treasure, come back and show me, and I'll tell you what I was able to research about it.
Good luck!

You get following hints from Dusty Giftwrap as well:
There are 3 buried treasures in total, each in its own uncharted area around Geese Islands. Use the gameboy cartridge detector and listen for the sound it makes when treasure is nearby, which gets louder the closer you are. Also look for some kind of distinguishing mark or feature, which could mark the treasure's location.
Listen for the gameboy cartridge detector's proximity sound that activates when near buried treasure. It may be worth checking around the strange toys in the Tarnished Trove.

We wander around a bit and find a place where the cartridge detector stops.

After returning to Dusty Giftwrap he tells us:
Whoa, you found it!
It's a... video game cartridge? Coooooollll... I mean, arrrrrr....
So, here's what my research uncovered. Not sure what it all means, maybe you can make sense of it.
You have all three? I think that makes you ruler of the pirates!

And he give us another hint:
1) Giving things a little push never hurts. 2) Out of sight but not out of ear-shot 3) You think you fixed the QR code? Did you scan it and see where it leads?

We start the game via the Items menu item. The buttons for operation are displayed in the game. After a short introduction, we get started. The task is to push the blocks into the correct position.

We find the blocks by firing musical notes at them, which requires a bit of trial and error. Music will play for a while and the correct destination will appear. We also take care not to push blocks in such a way that they can no longer be moved. If we talk to the character in the north, we can reset the game. Except for one stone, the destination is close by and immediately visible. The last block, which is relatively far to the left, must be moved to the right-hand side of the playing field. Then the music is enough to recognise the destination.

When all blocks are positioned correctly, the final QR code appears. We simply scan this with our mobile phone and are directed to https://8bitelf.com/.
This page shows us the solution: flag:santaconfusedgivingplanetsqrcode