When Reforged (released 2020) failed to meet expectations, many players in 2021 used a tool called "CASC Viewer" to extract the original 1.27-1.28 game files. They relied on FTP logs to reconstruct original patch sequences, essentially rolling back the client to the pre-Reforged "classic" mode that still recognized the old BNET FTP endpoints.
Before the era of battlenet: the Blizzard Launcher (and long before Microsoft’s acquisition), Blizzard Entertainment hosted a public FTP server. Located at ftp.blizzard.com (or ftp.battle.net ), this server acted as a massive, unadorned digital warehouse. ftp bnet 2021