Amazing, macOS 26 really is like Windows. My Mac Mini rebooted overnight to install an update, without asking, and despite the fact I left Xcode in the middle of a debugging session last night. There's a proud notification about "background security improvement". IT'S NOT A BACKGROUND IMPROVEMENT IF IT THROWS OUT MY WORK-IN-PROGRESS AND REBOOTS THE COMPUTER.
(Automatic updates were disabled, but I had left the "download security updates" option enabled. So I guess I have to disable that too.)
(Automatic updates were disabled, but I had left the "download security updates" option enabled. So I guess I have to disable that too.)