Note: That is based off the unstable branch and I do not recommend installing it on your system, this is just an ISO I use to test some crap. I am not sure why you need an ISO with 5.12 exactly, incompatible hardware?
I would recommend you to build your own ISO instead of downloading ISO out of other random people’s google drive on the internet. No offense but this is basic security principles.
Here is quick tutorial to build your own ISO very easily from GitHub:
change the kernel version in the config (and the profile to use, kde, xfce, gnome, whatever) and you’re done. Watch the video once, then try it following the video again, this is easy.
The live environment is immutable I think. What you install goes to the RAM if I’m not wrong (and is flushed on reboot), and nothing can be modified in the live environment as far as I know.