The announced release where the FirstPerson mod got cut back to its basics, to just contain FirstPerson, nothing else.
This means the file is about 40% smaller and has no dependencies anymore. (Except for the Fabric API on Fabric, also still recommending to install Not Enough Animations for a better experience(Marked here as required so the Curse Launcher downloads it too, but this mod technically works without it))
The removed submodels like PaperDoll, animations, and 3d-Skins can be found linked in the description, all available for Fabric/Forge and without requiring dependencies(except FabricAPI). Cosmetics will be worked on next, and be released sometime later.