The app ID generated for the catalog is different from the developer-provided ID found within the Microsoft Teams zip app package. The externalId value is empty for apps with a distributionMethod type of store. When apps are published to the global store, the id of the app matches the id in the app manifest.
The app is available to all tenants through the Microsoft Teams app store.
The app is available only in this tenant.
The app is available only to the user/team its installed to.