You're looking for information on Sildur's Shaders, specifically version 1.21.7!
Would you like more information on Sildur's Shaders, Minecraft, or shaderpacks in general?
Keep in mind that my knowledge might not be up-to-date, and I recommend verifying the information through official sources or forums.
As of my knowledge cutoff, Sildur's Shaders 1.21.7 is likely a shaderpack designed for Minecraft version 1.21.7. Here's a brief report: