https://www.lantis.jp/imas/ssr/

Special website for the IDOLM@STER MILLION LIVE! SPECIAL SOLO RECORDS CD series.

https://x.com/imas_lantis/status/1947944776952938591
There's a comment from Mirai's VA as the first CD to be released.

There's a review of it for some reason:
http://pylonport.bandainamcomusiclive.co.jp/recommendmusic/237

Also a Spotify playlist of the ALL versions:
https://open.spotify.com/playlist/4pTY2PXUvp0xTTmURF2YOI