Linux

Attempting to kill init means that something tried to kill PID 1. That's... abnormal outside of a shutdown. But it can be normal during shutdown. So uhh... yeah: if it continues to be a problem then it needs to be reported and fixed by your distribution. What distribution are you using?

I see kernel panics at shutdown most often on Arch-based distros after updating system packages.

It sucks when it happens during shutdown but it's typically not going to cause other problems... except perhaps not automatically booting if you wanted to reboot instead of shutdown.

I'd reinstall libpcre, looks like it's gotten broken?

The kernel panic should be a direct result of shutdown (which I guess at this point is init/pid1) not finding its dependency and killing itself.

Yes this is a kernel panic which occurs when something goes terribly wrong inside the system. This could be anything from broken software to defective hardware. You should observe if this happens regurlarly.

You could look at the package that's mentioned in the first line in Synaptic. The error message says it can't find a file. Fürst thing is do is check if that fike is actually there.

Your libpcre seems broken. Reinstall the package that contains this file.

As others said, check if it is a single case or if it repeats at the next shutdowns. Anyway, the main question this brings to mind is: do you have a good backup of your system / data ?

Personally I'd be worried there's a transient disk issue. I'd ensure my backups are good and files aren't being silently corrupted. I assume you're on an NVME, they tend to fail instantly, but sometimes you'll get transient file errors beforehand (like not being able to open a system library). Look at something like debsums to start with maybe.

Could also be an SEU

You seem to have removed libpcre2 library. Try to reinstall it using your package manager.

In addition to the other things mentioned, check the health of your drive. This could be a symptom of corruption.