First Wonder Box Trade Eevee .

Using the mobile app, when the player deposits a Pokémon into the Wonder Box, and that Pokémon was then traded away,
the player would then be qualified to receive this Eevee from the Mystery Gift > Gift Box option.

Basically, the player gets the Eevee for their first successful trade via the Wonder Box.
 

As per any Mystery gift redeemed on Pokémon HOME, this Pokémon's language follows the language that was set on the mobile app.
This Pokémon's OT Gender follows the gender of the avatar the player picked.