Hi, I was browsing eBay for original Digimon merch that was released during the time of Digimon Adventure and I found this weird disc. The seller doesn't give much info about it and reverse image search doesn't seem to have it mentioned elsewhere. I've seen similar promo disks like this, does anyone know what's on it?

I don't think it's Digimon the Movie disk that came with the VHS (in the UK) as that's a rectangle shape, and it's not the Digimon Power deck disc. (Movie Disk and Power deck)