Redshift is an open-source screen color temperature adjustment tool that automatically adjusts the screen temperature based on time to reduce blue light stimulation and help protect vision. It works by automatically adjusting the screen temperature based on geographical location and time, with higher temperatures during the day and lower temperatures at night. Redshift can be installed easily on Ubuntu and configured either through the command line or a configuration file. Users can set parameters such as latitude, longitude, and color temperatures for a smooth transition. This tool is beneficial for eye protection and maintaining visual health.