Implementing MTE is mostly another step in Apple’s efforts towards memory safety. There are bunch of things they’ve done to try to make this work a little better, but for obvious reasons, this is never going to be turned on by default for user apps and is only enabled for specific pathways.

> Because EMTE tag checking imposes a performance cost, we designed Memory Integrity Enforcement to take advantage of our secure allocators first and use EMTE to protect only smaller individual allocations within a type bucket, which software allocators can’t defend on their own.

Which seems to imply that outside of Apple’s targeted use in the kernel, the developer use of MTE on Apple platforms requires that you migrate your code to use their typed allocators…which I don’t know how many people are going to do that (and it is clear their answer is going to be to point people to Swift since it makes these types explicit for the compiler and even then, I am sure there are bugs in Swift in certain cases). Memory tagging is neat tech, but I don’t know if it’s going to gain all that much traction. It requires a burden that I suspect most app developers are not willing to take on and given that the user interaction is a crashy app. This is a path to nowhere except those of us who understand the trade-off.