We can easily identify the Marketing App and the environment in which it has been provisioned.
Login to Power Platform Admin Center >> Resources >> Dynamics 365 Apps
https://admin.powerplatform.microsoft.com/
We can find the unique name of the environment/organization suffixed with the name of the app i.e. Dynamics 365 Marketing Application for the configured app.
Navigate to the environment’s Advanced Settings >> Customizations >> Developer Resources
We can find the Unique Name of our organization there
Hope it helps..