Today GOTD offered a collection of LUT files, so thought a few words & a couple of links might be useful. If you change the overall colors or tint when editing a photo or video, you can basically save the color/tint adjustments you made as a sort of preset -- by saving a LUT file, you can later use that file to make another photo or video look similar. It's used more in video than with photos, usually working to provide a certain look, e.g. across a series or set of photos you took in the same place. LUTs come in a small variety of formats -- I think the .cube files in today's GOTD are more often used with video editors. Not all video or photo editing apps let you work with LUTs -- if the apps you use do not, it's usually not that big of a deal, so maybe don't rush out to switch your software.
skylum[.]com/blog/what-is-a-lookup-table-lut
wikipedia[.]org/wiki/Lookup_table
wikipedia[.]org/wiki/3D_lookup_table