| chi | CUHP Input Data |
| chi | Tombo Encrypted Data |
| chj | IBM SPSS Interview Cache |
| chk | DB/TextWorks Check Textbase Problem Report |
| chk | Epidata Defined Checks |
| chk | Gaussian Checkpoint File |
| chk | NVU CHK Data |
| chk | Polyspace Check Results Data |
| chk | Saved File Fragment |
| chk | Sophos Anti-Virus Intercheck Data |
| chl | Chromeleon Channel Raw Data |
| chl | ConTEXT Highlighter Data |
| chl | RealPlayer Live Channel Data |
| chls | Charles Session Data |
| chlsj | Charles Proxy Recording Data |
| chm | ChemDraw Chemical Structure |
| chm | SWAT Soil Chemical Input Data |
| chml | Chameleon Studio Database |
| chn | Ethnograph Data |
| chn | MODELLER Sequence PIR Data |
| chn | MODTRAN CHN Output File |
| chn | Unreal Engine Chinese Language Data |
| cho | Animation Master Choreography Data |
| cho | CUHP Output Data |
| chp | Affymetrix Probe Array Results File |
| chq | Help Combined Full-text Search |
| chr | Advantage Database Server Character Set Data |
| chr | Altair FEKO FEST3D S-parameter Matrix Data |
| chr | Autodesk 3D Studio Max Character File |
| chr | Nintendo DS Character Data |
| chr0 | Nintendo Wii Model Animation Data |
| chro | RelEx Chromatograms Data |
| chs | Corel Presentations Charts Style Data |
| chs | MotionTracking Chromatic Shift Correction Data |
| cht | eSignal CHT Data |
