Yes, I'll grab some studies now... You don't notice it, either, when you use it - your eyes quickly adjust.

Edit: https://academic.oup.com/jcem/article-lookup/doi/10.1210/jc.2003-030570

Has it been shown to work? Looks pretty ugly imo, and I've had no trouble with a non-red-shifted screen(monitor) before bed.

As Miscenco said, it's a filter named Twilight, which puts a red tinge on the screen as it gets later, in an attempt to reduce blue light, in order to prevent screens keeping you more awake later at night.

Blue light filter, probably. They're really handy. 

59, but I was quite a fan of prestiging fast earlier.

Free at last