Luke

It is probably a good idea to mention what Redshift actually is, since it’s far from the top result in a search, and a lot of people associate that word with an AWS product by the same name. Wikipedia describes the Redshift you presumably mean as:

an application that adjusts the computer display’s color temperature based upon the time of day.

It also mentions that gammastep is a more recent fork, but it has not had any commit activity for 2.5 years, so gammastep might be abandoned as well.

I’m looking for a PDF viewer which would allow me to go from one PDF file to another without going back to the file explorer. In a way, I’d want it to work a bit like an image viewer where you only have to click on an arrow to go to the next image.

GNOME sushi kinda works like that, especially if you restrict a nautilus window to only showing PDFs (e.g., by searching for pdf first). Then you hit space and it opens the preview, and you can arrow left and right to move to the next match without explicitly tabbing back to nautilus first.