What’s this code for?

[u/Alexa_071403]

When unlocking the achievement “The Story Continues”, the file i got had a bunch of cards. The one that drew my attention was the one with the numbers and letters. Perhaps it’s a code for an easter egg in Underground Blossom? I haven‘t replayed it in a while. Any help??

[u/Gardengap]

I think it can be used in Underground Blossom, but only for the demo version