Move the .jar file into your Minecraft mods folder.
Version 0.8.1 is specifically built for the Minecraft 1.19.x update, ensuring it plays nice with other performance staples like Lithium and Sodium . Is It Still Relevant? phosphor-fabric-mc1.19.x-0.8.1.jar
Minecraft’s vanilla lighting engine is notoriously inefficient. Whenever a block is placed or a chunk is loaded, the game calculates light levels for every surrounding block, which can cause massive "lag spikes." Phosphor rewrites these calculations to be significantly faster. Move the