Weird AT&T Treasure Hunt?

[Thalia]

I've been exploring around as Knuckles trying to find some emblems, but when I went to the Mystic Ruins the entire area was littered with these signposts that say "Dreamcast AT&T Worldnet Service".

I play the game with the SADX mod, so I know it's some old Dreamcast DLC. I have to find 4 treasures which are hinted at by the signs, but I think I've read every sign in the area and only 3 treasures are hinted towards, so it seems impossible to complete.

I decided to look up a walkthrough or something but I cannot find a single mention of this anywhere on the internet. You'd think it would be easy to find with such a bizarre and specific combination as Sonic and AT&T too. So has anyone here on steam actually done this? I am really curious what the "prize" could possibly be.

[F-Man]

There are two in the center of the 4 signs facing each other. One is at the crosspoint of all 4, and the other is at a punch strike's length in front of the shack.

By the way, you might want to update your mods and mod loader, as per the default settings right now August 31 should be the Reebok challenge DLC (and September 1 the Dreamcast Launch). The latest DLC mod version is 2.03.

[F-Man]

Oh for the prizes I could find the information on the description for this video: https://www.youtube.com/watch?v=SBzny2YMTjM The grand winner is even in the comments.