| stq | STATISTICA Text Data |
| stskin | Steam Customizer Skin |
| sumocfg | SUMO Configuration |
| swgo | Switch Go Configuration |
| sxcu | ShareX Custom Uploader Configuration |
| sxp | Xen Configuration File |
| sxx | Adobe Flash Player Shared Object Settings File |
| sys | Windows System Configuration |
| t4 | TerrAlign Alignment Configuration |
| tam | Tame Settings |
| tbf | Cadvance Toolbar File |
| tbk | TQSL Configuration Backup |
| tccfgextender | TestComplete Tester-specific Settings Data |
| tci | TCINV Inversion Control File |
| tclogs | TestComplete Log Configuration File |
| tcls | TestComplete Configuration File |
| tcnet | TestComplete Configuration Reference File |
| tel | NCSA Telnet Configuration File |
| terminal | Terminal Settings Data |
| tf | Borland Turbo Configuration |
| tfd | TFSImage Settings |
| tgb | TheGreenBow VPN Client Configuration |
| thc | AbleCommerce Wizard Theme Configuration |
| thc | Therion Configuration File |
| ti0 | Tabula Initialization Data |
| ti1 | Tabula Initialization Data |
| ti2 | Tabula Initialization Data |
| timer | Systemd Service Timer Configuration |
| tiw | Bentley InRoads Wizard Settings Data |
| tlp | Tunnelier Profile |