GNU/Linux Debian Installing Redshift Guide
You Are Welcome! The Tutorial Shows You Step-by-Step How-to Install Redshift in Debian GNU/Linux Desktops.
And Redshift for Debian adjusts the Color Temperature according to the position of the Sun.
So as a Blue Light Filter a different Color Temperature is set during Night and Daytime.
Moreover, during twilight and early Morning, the Color Temperature transitions smoothly from Night to daytime temperature to allow your Eyes to slowly adapt. At Night the Color Temperature should be set to match the Lamps in your Room.