| Definitions |
| Colors | Description of UO's 16-bit color values |
| Index Files | Format of the generic index file |
| Anim.mul | Animated character/equip graphics |
| Anim.idx | Index file for Anim.mul |
| AnimData.mul | Data for static animations |
| Art.mul | Land, static, and UO alpha graphics |
| ArtIdx.mul | Index file for Art.mul |
| Fonts.mul | Nine character sets |
| GumpArt.mul | Gump interface graphics |
| GumpIdx.mul | Index file for GumpArt.mul |
| Hues.mul | Hue coloring tables |
| Light.mul | Additive lightmap graphics |
| LightIdx.mul | Index file for Light.mul |
| Map<n>.mul | Land Matrix |
| MultiMap.rle | Overhead Map View |
| Multi.mul | Multi item lists |
| Multi.idx | Index file for Multi.mul |
| Palette.mul | 24-bit RGB palette of unknown use |
| RadarCol.mul | Tile->Color table |
| SJIS2Uni.mul | Conversion table from SJIS to Unicode |
| SkillGrp.mul | Defines what skills are in which groups |
| Skills.mul | Skill table |
| Skills.idx | Index file for Skills.mul |
| Sound.mul | Sounds (PCM 22.050 kHz, 16-Bit Mono |
| SoundIdx.mul | Index file for Sound.mul |
| Speech.mul | Keyword/ID table |
| StaIdx<n>.mul | Index file for Statics.mul |
| Statics<n>.mul | Static item lists |
| TexIdx.mul | Index file for TexMaps.mul |
| TexMaps.mul | Ground texture graphics |
| TileData.mul | Data about tiles (flags, properties, name) |
| UniFont[n].mul | Unicode character set |
| VerData.mul | Patch data |
