Can an app like Instagram block the share extension of my app so that it no longer appears in the available share extensions for this particular app on my iPhone? Example: I’ve created a new messenger app. Can Instagram block the share extension of my messenger app so that the user of my messenger won’t be able to share Instagrams content (via more options menu ••• -> share to…) with my messenger anymore? Is there a way to avoid this behavior? Or a legal and handy workaround?