Hi, I wondering differences between Ubuntu Touch and other Linux distros on mobile. I found answers to many of my questions, but not a few of them. Them are:

Is libhybris/helium basically just translator for syscalls? If it is, why? I mean, most of syscalls are the same in Android and Linux kernel.

Can Android kernel without libhybris/halium run "standard" Linux kernel binaries? Can it runs e.g. grep binary from Arch ARM?

Apparently, libhybris/halium are not the reason for the difference between Ubuntu Touch and other distributions. Are the differences due to the fact that they limit the installation of applications to Clicks packages by default? As Fedora Silverblue limit user to Flatpaks?

How does the UI framework limit the applications that can be installed? Can't the applications use whatever UI library they wants?

I thinked that Droidian are similar limited OS like Ubuntu Touch because it also use Halium etc. Apparently it isn't the case, so is Droidian just Mobian with Android kernel? I can install binaries from ARM Arch and Flatpaks to it?