This git repo used to include disassembled source code for the Windows version of inAudible. The author reached out to me and respectfully and clearly expressed that I should remove the source code and that s/he is fine with the installer being here. Additionally, the author pointed out that "All of the opensource Audible projects on the web (ffmpeg, inaudible-ng, etc.) are using code that I created and specifically contributed to these projects."
In other words: the most powerful bits of code for removing the DRM are still available to all. My thanks to the author for contributing this code to the community.
Among the ffmpeg library's versatile options is the ability to remove DRM from .aa and .aax files. However, command line programs can be intimidating and cryptic. inAudible eliminates the intimidation and also adds several other features. Unfortunately, inAudible is currently only available on torrenting sites. Torrenting is a way of distributing any kind of file but it has a bad reputation due to being a popular method of pirating media and software. This gives many people pause about obtaining inAudible even though it is neither pirated nor illegal. Also, torrenting sites are sometimes blocked by work, schools, public hotspots, and internet providers. This can make it impossible to obtain inAudible.
This github repository makes available the inAudible install files.