Unity 4.x has a different AssetAny media or data that can be used in your game or Project. An asset may come from a file created outside of Unity, such as a 3D model, an audio file or an image. You can also create some asset types in Unity, such as an Animator Controller, an Audio Mixer or a Render Texture. More info
See in Glossary Bundle system compared to 5.x. The following pages document the legacy (4.x) asset bundles.