The pack should appear in the list. Move it to the right side to activate it.
X-ray texture packs are specialized resource files that make standard blocks (like stone, dirt, and gravel) transparent while leaving valuable ores—such as diamonds, gold, and iron—fully visible. This allows players to "see through" the ground to locate hidden caves and resources quickly. How to Install an X-Ray Pack in Eaglercraft xray texture pack 188 eaglercraft 2021
Are you trying to use it in or on a multiplayer server ? Share public link The pack should appear in the list