Origami cranes in the games:
http://wccftech.com/how-to/another-code-recollection-guide-how-to-find-14-two-memories-origami-messages/
http://wccftech.com/how-to/another-code-recollection-guide-how-to-find-another-code-r-origami-messages/

Tweet detailing the discovery:
http://twitter.com/Adr0t/status/1765119007584039105

Another Code microsite:
http://www.nintendo.co.jp/ds/anoj/index.html

Another Code: R microsite:
http://www.nintendo.co.jp/wii/rnoj/index.html

Method:
- Look up the file "ditem_PaperCrane" inside Textures2D of the game's data.
- Stitch the texture together into one complete QR Code if necessary.
- Scan it with any QR Code decoder like the one used in smartphones. Resize if necessary.
- QR Code should display the following: http://www.nintendo.co.jp/ds/anoj/index.htmlhttp://www.nintendo.co.jp/wii/rnoj/index.html

The code can be recreated by inputting these URLs exactly as they are shown above into the following Japanese QR Code generator:
http://qr.quel.jp/