| 41. | .skp | application/vnd.koan ◊ application/x-koan |
| 42. | .skt | application/vnd.koan ◊ application/x-koan |
| 43. | .sl | text/vnd.wap.sl ◊ application/x-seelogo |
| 44. | .slc | application/vnd.wap.slc ◊ application/x-salsa |
| 45. | .slides | application/x-showcase |
| 46. | .slt | application/vnd.epson.salt |
| 47. | .smd | chemical/x-smd |
| 48. | .smi | application/smil ◊ chemical/x-daylight-smiles ◊ chemical/x-x-daylight-smiles |
| 49. | .smil | application/smil |
| 50. | .smp | application/studiom |