– **.mcpack:** Contains *either* a Resource Pack (textures/sounds) *or* a Behavior Pack (logic/entities). You may need to install two separate .mcpack files for a full mod.
– **.mcaddon:** A bundle that contains *both* the Resource Pack and the Behavior Pack in one file.
**Which to use?** Always prefer .mcaddon for a seamless one-click installation. If you only want to change the look of the game, a Resource .mcpack is sufficient.
