Minecraft Wiki
Not to be confused with MCD:Launchpad.

The Minecraft Dungeons Launcher was the login and downloader front-end to the Minecraft Dungeons client, that was available for Windows. Its purpose, before being later merged into the Minecraft Launcher on November 27, 2020, with 2.2.74x, was to launch the Game under a Microsoft account as at the time the Minecraft Launcher was incapable of supporting Microsoft accounts. Soon after the merge the Minecraft Dungeons Launcher became incapable of launching Minecraft Dungeons on January 18, 2021.
Currently, the Minecraft Dungeons Launcher is available to download, but is rendered unusable with a message displaying to play in the Minecraft Launcher being the only thing to appear.