| extension name | file type | Classification |
|---|---|---|
| HBK | Mathcad Handbook File | text file |
| HHT | Help and Support Center HHT File | text file |
| HS | Java HelpSet File | text file |
| HWP | Hangul (Korean) Text Document | text file |
| HWP | Hanword Document | text file |
| HZ | Chinese (Hanzi) Text | text file |