Is there any evidence F.lux and similar actually do anything other than make pretty lights? I mean, that's fine enough if that's what you want but I often hear health or sleep claims made. Are those substantiated in any way?
tl;dr - for the core phone/laptop F.lux use case, no, it isn't substantiated
https://www.health.harvard.edu/staying-healthy/blue-light-ha...
We kind of even know why, because of blue light receptors in our eyes linked to hormones released in the morning to increase alertness. This is linked to the light spectrum seen at sunrise.