"I don't understand the new feature" is not a good problem description. I don't think you can get a personal tutor for free at Linuxquestions.org. What you can do is search the internet for
ARM64 pointer authentication to get a description of this technology, then ask a more specific question.
Having said that, I scanned
https://www.andreasch.com/2018/09/20...ation-pointers and believe that this feature attempts to prevent exploits that rely on changing pointer values. Pointers in the kernel are cryptographically signed so that they can't be tampered with. This feature is specifically targeted to smartphones with ARM processors.