+Explanation: https://debian-handbook.info/browse/stable/sect.apt-get.html#sect.apt.priorities
+Explanation: And man apt_preferences
+Explanation: Installed packages get 100 priority, so this won't upgrade testing
+Explanation: packages unless explicitly asked to.
+Explanation: Install with apt-get install package/testing. But if dependencies are
+Explanation: needed, or need upgrading,
+Explanation: apt-get -t testing package, setting testing to priority
+Explanation: 990 just for that command.
+Explanation: Use apt-cache policy to verify these settings.
+Package: *
+Pin: release a=testing
+Pin-Priority: 50
+
+Package: *
+Pin: release a=testing-updates
+Pin-Priority: 50
+
+Explanation: Allow this testing package to automatically upgrade.
+Package: unison
+Pin-Piority: 100