Andronix is simple inside the hood (well not really, but most of it is simple to understand). Andronix uses PRoot to run your favourite Linux distribution on your Android devices.
As stated in the official website of PRoot
PRoot is a user-space implementation of chroot, mount --bind, and binfmt_misc. This means that users don't need any privileges or setup to do things like using an arbitrary directory as the new root file system, making files accessible somewhere else in the file system hierarchy, or executing programs built for another CPU architecture transparently through QEMU user-mode.
or in easier words, the benefits of enabling PRoot include running Linux operating systems in a Termux chroot on an Android smartphone, tablet and Chromebook.
We use Termux to provide the command line and the packages that are especially compiled for Termux implemented inside Andronix.
Yes but no. Andronix is partially open-source. All the free distro tar files and the shell scripts are available on our GitHub repository. While all the paid things, like the actual Android app and all the files concerning Andronix Modded OS are close-source for obvious reasons.
That doesn't mean that we don't love open-source, we ❤open-source. In fact if you're a developer or a maintainer of an open-source project, we will be more than happy to provide you everything for free for life. Just get-in touch with us and complete the process of verification😊.