The Web Archive's preservation of Windows Movie Maker involved a multi-step process. First, the organization obtained a copy of the software from Microsoft's own servers, which were still hosting the program at the time of its discontinuation.
You cannot download Windows Movie Maker from Microsoft anymore. Microsoft’s official download links redirect to a support page stating the product is discontinued. Searching generic download sites (CNET, Softonic, FileHippo) is a minefield of malware, bundled adware, and fake "installers." windows movie maker web archive