| 91. | .hwp | Korean word processor document format (HanGul) |
| 92. | .hx | Cross-reference hash file (THOR database) |
| 93. | .hxm | Alternate Protocol Selection menu for all users (Procomm Plus) ◊ HAM extension (Descent 2) |
| 94. | .hxx | C++ header |
| 95. | HxA | MS Help 2 Files Attribute Definition File Defines topic attributes and filter definitions. |
| 96. | HxC | MS Help 2 Files Collection Definition File. Identifies all other key files and compiler options. Defines navigation data monikers. |
| 97. | HxE | MS Help 2 Files Sample Definition File Optional file for defining samples. |
| 98. | HxF | MS Help 2 Files Include File Lists all files to be included in the compiled HxS help file. Supports *.*, *.HTM, *.HTML type syntax. |
| 99. | HxK | MS Help 2 Files Index Defn File (Internal Name=K) KLinks. Keyword Index appear in the viewers Index navigation control. Typically named "K". ◊… 0.6 KB |
| 100. | HxT | MS Help 2 Files TOC Definition File Table of contents definition file. |