This is a repository that tracks all the scripts and other tools for removing DRM from ebooks that I could find, committed in date order as best as I could manage. (Except for the Requiem tools for Apple's iBooks, and Convert LIT for Microsoft's .lit ebooks.) This includes the tools from a time before Apprentice Alf had a blog, and continues through to when Apprentice Harper (with help) took over maintenance of the tools.
For the latest Amazon KFX format, users of the calibre plugin should also install the KFX Input plugin from the standard calibre plugin menu. It's also available from the MobileRead thread here: https://www.mobileread.com/forums/showthread.php?t=291290
I welcome contributions from others to improve these tools, from expanding the range of books handled, improving key retrieval, to just general bug fixes, speed improvements and UI enhancements.
I urge people to read the FAQs. But to cover the most common: Use ADE 2.0.1 to be sure not to get the new DRM scheme that these tools can't handle. Do remember to unzip the downloaded archive to get the plugin (beta versions may be just the plugin don't unzip that). You can't load the whole tools archive into calibre.