| Steam Client Registry Format | |
| Valve | |
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File with a BLOB extension contains different types of data to which the Valve Corporation's Steam application can refer to. General BLOB files are stored with the .BLB extension.
Steam application is used to distribute applications across the Internet. Within BLOB files, information on a registry of users of ClientRegistry.Blob or on updates (AppUpdateStats.Blob) is contained.
| .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 |