Nightmode9 (iOS 9) cydia tweak offers a means to elegantly reduce the brightness of many applications on iOS 9.
Nightmode9 is a refactor of the original Nightmode with added functionality and a wide variety of improvements. It offers users the option to set one an amount of predefined colour schemes and alternatively the option to create their own colour profile. Most importantly Nightmode 8 offers improvements in stability and extends compatibility to more applications.
It includes support for both first and third-party applications and has a variety of options. Nightmode can be toggled and scheduled with an Activator or Flipswitch action which offers clean integration with regular usage.