# subscript(_:) The custom attribute of type `T` associated with the run of glyphs, or nil. If no run contains the custom attribute we also check its attachment’s runs. ``` subscript(key: T.Type) -> T? where T : TextAttribute { get } ``` --- 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)