The context describing where your iMessage app is presented.
- iOS 12.0+
By default, the system only displays iMessage apps in the
MSMessages context (the iMessage app only appears inside the Messages app). iMessage apps in the media context have additional limitations and design considerations.
You can control the supported contexts by adding the
MSSupported key to the iMessage app extension’s
info file. For example, Listing 1 enables the iMessage app in effects in Messages and FaceTime.