If you found this link on a site like Mega.nz or MediaFire , check the original post (often on a forum or a Twitter/X fan account) for the decryption key.
Suisei often hosts "unarchived" karaoke streams where the VOD is deleted immediately after the broadcast due to copyright. Fans often share these via private links or file-sharing sites with standardized names like TalentNameYYYYMMDD . How to Find the "Missing Piece" (Password/Source) Download Suisei20210714 rar
If you have the file but need a password or a way to open it: If you found this link on a site like Mega
On , Suisei participated in a few notable activities that fans typically archive: How to Find the "Missing Piece" (Password/Source) If
You can look for corresponding stream metadata on the Hololive Fan Wiki to see if that date matches a known deleted stream.
Weekly radio broadcasts are frequently archived by international fans as .rar or .zip files since they aren't always permanently available on YouTube.