The Dig! Dig! Digger function was a Pocketstation peripheral for the Playstation 1 that you slotted into the Memory Card port. It functioned like a memory card and a pseudo-Tamagachi thing that also added some additional stuff to the game if it supported it. Thing is, it was never released outside of Japan, and it sold poorly besides, so its lifespan was only three years before Sony discontinued it.

Squaresoft tried to jump on it, and Final Fantasy VIII and SaGa Frontier 2 in their western releases, both prominently feature points in the game where you're supposed to access the Pocketstation. For many, it was a mystery what Go! Go! Digger (Dig! Dig! Digger in the Remaster) was even supposed to be, which was irritating if you found these points in the game, some of which are a little obscure.

But now the mystery is finally solved, after 25 years.

-- Cap --

In Gustave & The Blacksmith, examine the drawers in the house to the southwest.

-- Harold --

During Infiltrating Alexei's Gang, talk to the man in Thermes at the counter behind Cordelia.

-- Barkley --

In Showdown With The Egg, talk to the guy standing on the roof in the inner settlement.

-- Anna --

During any visit in Northgate as Ginny, examine the northeast end of Northgate.

-- Mayor --

Build all three entertainment districts during "Constructing Hahn Nova", then talk to the mayor at the northern district during "To Gustave's Stronghold".

-- Masa --

Talk to the guard in Gruegel in front of the palace.

-- Gingar --

In Conquest of Wide, speak to the squirrel-mount things at the stable.

-- Yuka --

In Desert Megalith, talk to the girl in pink running around and choose the option "That's for sure". This is RNG-based, so keep talking to her until she relinquishes the digger.

-- Tono --

In the City of Night, on the screen with the trader, check the branch on the left before the second flight of stairs for something glowing on the ground even with all the lights on. There will be a wandering NPC who may get in the way.

-- Androla --

In Laubholz, talk to the woman in the corner of the restaurant next to the guitar. Enjoy listening to Botschaft while you're at it.

-- Inko --

In Weissland, talk to the woman in the inn sitting alone at the table.

-- Ailin --

In Vogeland, talk to the girl with pigtails in the tavern.