Night mode is an automatic setting which takes advantage of the new wide-angle camera that's in the iPhone 11 and 11 Pro models. It's equipped with a larger sensor that is able to let in more light, allowing for brighter photos when the light is low.
macOS Catalina Now Available
Dashboard Feature Eliminated in macOS Catalina
The Dashboard option, first introduced in OS X 10.4 Tiger, used to be a prominent Mac feature, housing sticky notes, a weather interface, a clock, a calculator, and other customizable widgets.
It was disabled by default starting in macOS 10.10 Yosemite, and in the current version of macOS, Mojave, it's still disabled unless you seek it out, enabling it as part of Mission Control or adding it to the Dock.
In Catalina, there is no more Dashboard app at all, as pointed out by Appleosophy. It can't be enabled via Mission Control and there's no sign of it in the operating system, marking its official demise.