Brightness control for Night Light
Feature summary
Add an option to control brightness/gamma in addition to color temperature to Night Light.
How would you like it to work
Add a dconf setting for Night Light "nightlight.brightness". When set, the brightness/gamma would be reduced gradually with the color temperature when Night Light becomes active (similar to the functionality in redshift).
If you think it would be widely used, you could also add a second slider under the "Color Temperature" slider labelled "Brightness".
Relevant links, screenshots, screencasts etc.
This feature is present in redshift: http://jonls.dk/redshift/