If you're not accustomed to it, arm computers have no BIOS/UEFI boot selection and usually require a custom bootloader to load a new OS. I remember many fun hobby projects of old with x86 where I could take an old x86 appliance and put in a clean linux disk to use the hardware however I wanted, nowadays your OS needs to be signed, and because the root is owned, the software can be limited to that what the OEM or OS company desires, much like what MS is trying to do with TPM2 and Win11. Of all the ARM phones I've seen, perhaps 10% support bootloader unlock, and that's only with a certain carrier, the problem is that it's not a unified platform, support has to be implemented per-device, so even if the bootloader is open, the OS may not be up to date (as many have noted with dodgy third party arm boards)

Just think about how few Android devices have an open bootloader right now, there's no reason to think it'd be any different on larger hardware.

On the flip side, every Chromebook and Chromebox has a unlockable and open-spurce coreboot bootloader.

I love their mechanism where one opens the device and removes a screw to unlock it. Very novel and honestly kind of fun.

We used to call installing software on our own device, installing.

MacOS requires dropping to the terminal to install unsigned applications. There is literally no need for this, except to ensure apple profits.

When do you see this? For me, I just go to System Settings → Privacy & Security. Scroll down to Security and look for the message about the blocked app, click Allow Anyway, and then reopen the app.

If I install Xournall++[1], just opening the application will fail and MacOS will ask me to move it into trash. I am required to execute `xattr -c /Applications/Xournal++.app` to "remove quarantine".

I just reinstalled and can confirm that I don't see anything in the System Settings as you say.

[1] https://github.com/xournalpp/xournalpp/releases/tag/v1.2.8