Using Light Master files will allow more plugins to be loaded than the previously possible due to the 8-bit plugin ID limit of 255. esl file extension is a new optimized file format introduced in the patch 1.10 update. They are intended for use with player mods, as base games and their DLC are both packaged with. esp file extension, (also called an ESP file, short for Elder Scrolls Plugin) are largely identical to master files in structure but are loaded after them, and are unable to modify other plugin files.
