What are loose files in the context of npc beautifiers?

[wholegrain]

Is it an optional file or a file that is necessary so that the mod you downloaded work correctly? JH npcs uses a loose file for one of its mod.

[Yuuen]

Optional, usually for performance or if you get problems with textures or conflicts etc.

[myuhinny]

Opional could be different texture files body files clothing or clothing colors. Loose files are any file that is found in your skyrim data folder that is not is a BSA. BSA's load first when the game starts any loose file will trump any file inside a BSA file because they load last so when the game loads up the loose file will be what appears in game.