| OS/2 Configuration | |
| IBM | |
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CH extensions were used by OS/2 operating system files. OS/2 was developed by IBM and Microsoft as a Desktop PC operating system that implemented many features of Windows and Unix systems.
CH files were used for storing system configuration settings. OS/2 has been officially discontinued in 2006. CH format is now considered obsolete.
Updated 04/27/2022
| .a2theme | Aston 2 Theme Format |
| .acb | Adobe Color Book Format |
| .acbl | Adobe Color Book Format |
| .aco | Adobe Photoshop Color Palette And Swatches Format |
| .acrobatsecuritysettings | Adobe Acrobat Security Settings Format |
| .acrodata | Adobe Acrobat Data Format |
| .acv | Adobe Photoshop Colour Curves Format |
| .acw | Microsoft Accessibility Wizard Format |
