As part of the promotion for the movie Detective Pikachu, when players visit a Target store in the US and use the Pokémon Pass application on their smartphones, they were given a serial code that can be used with Let's Go Pikachu & Eevee.
Distribution of serial codes ran from May 11 to June 23, 2019. The code must be redeemed by August 29, 2019.
Shiny Eevee were gifted to Let's Go Pikachu, and Shiny Pikachu were gifted to Let's Go Eevee.
Format Ver.1.0.8-3b4, Post Updated Date:20191101_0402
What can be done with these files
PKM creation with PKHeX (drag & drop the wondercard file in the spot where you want the Pokémon)
In-Game Mystery Gift redemption with Switch Gift Data Manager