# Format reader property list dictionaries Include property list dictionaries to describe a format reader and register the formats it supports. ## Discussion An `ExtensionKit` format reader needs to include one required dictionary and can also include an optional dictionary in its `Info.plist` file: 1. `EXAppExtensionAttributes`: A required dictionary that describes the format reader and contains the following keys and values: - [`kMEFormatReaderClassImplementationIDKey`](/documentation/MediaExtension/kMEFormatReaderClassImplementationIDKey): The identifier for the format reader. Format similarly to the bundle identifier. - `EXExtensionPointIdentifier`: The extension point name for format readers. Set to the value for [`kMEFormatReaderExtensionPointName`](/documentation/MediaExtension/kMEFormatReaderExtensionPointName). - `EXPrincipalClass`: The name of the format reader factory class that conforms to the [`MEFormatReaderExtension`](/documentation/MediaExtension/MEFormatReaderExtension) protocol. - [`kMEFormatReaderFileNameExtensionArrayKey`](/documentation/MediaExtension/kMEFormatReaderFileNameExtensionArrayKey): An array of strings that specify the file name extensions that the format reader supports. - [`kMEFormatReaderUTTypeArrayKey`](/documentation/MediaExtension/kMEFormatReaderUTTypeArrayKey): A key to the array of Uniform Type Identifiers that the format reader supports. - [`kMEFormatReaderObjectNameKey`](/documentation/MediaExtension/kMEFormatReaderObjectNameKey): A user-readable string that describes the format reader. 1. : An optional dictionary that registers the formats from the [`kMEFormatReaderUTTypeArrayKey`](/documentation/MediaExtension/kMEFormatReaderUTTypeArrayKey) array that the format reader supports, so the system can recognize those media files and open them in the appropriate app. It contains the following keys and values: - : A user-readable string that specifies the media kind, which Finder displays. - : An array of `UTType` identifiers, with the first entry set to `com.apple.mediaextension-content`. This type also conforms to higher level abstract types such as `public.movie` and `public.audiovisual-content`. This array can include additional types as needed. - : This value needs to match the value for `kMEFormatReaderUTTypeArrayKey` in the `EXAppExtensionAttributes` dictionary. - , `public.filename-extension` key: This value needs to match the value for [`kMEFormatReaderFileNameExtensionArrayKey`](/documentation/MediaExtension/kMEFormatReaderFileNameExtensionArrayKey) in the `EXAppExtensionAttributes` dictionary. - `public.mime-type`: This is an optional key to a MIME type that corresponds to the format. For general information on how to make a `UTExportedTypeDeclarations` dictionary, see . ## Topics ### Property list keys [`kMEFormatReaderClassImplementationIDKey`](/documentation/MediaExtension/kMEFormatReaderClassImplementationIDKey) The unique identifier for the format reader. [`kMEFormatReaderExtensionPointName`](/documentation/MediaExtension/kMEFormatReaderExtensionPointName) A key to the extension point name for format readers. [`kMEFormatReaderFileNameExtensionArrayKey`](/documentation/MediaExtension/kMEFormatReaderFileNameExtensionArrayKey) A key to the array of file extensions that the format reader plug-in supports. [`kMEFormatReaderUTTypeArrayKey`](/documentation/MediaExtension/kMEFormatReaderUTTypeArrayKey) A key to the array of Uniform Type Identifiers that the format reader supports. [`kMEFormatReaderObjectNameKey`](/documentation/MediaExtension/kMEFormatReaderObjectNameKey) A user-readable string describing the format reader. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)