Cannot explicitly add Activity Action to A Package
|Knowledge Article Number||000247181|
|Description||When we create some custom actions on Activity object, and then we try to add those actions to a package, they are not available.
When we create some custom actions on other objects like Account, Contact, or custom objects, such actions are available when we add Actions to a package.
|Resolution||This behaviour is expected and by design.
The only way to add custom actions on Activity object to a package is via implicit method, eg, you can add them to a page layout, and then add the page layout to a package, this way they will be implicitly added to the package.