In AEM as a Cloud Service, multi-tenant projects can be managed via independent repositories linked to a primary project repository using git submodules. When a new tenant is added, the tenant’s repository must be registered as a submodule of the main project so that it is included in the CI/CD build and deployment pipelines.

From Adobe Documentation:

“When using independent repositories for tenant modules, these repositories must be referenced as git submodules in the main project repository. This ensures they are included in the Cloud Manager build and deployment process.”

— Adobe AEM as a Cloud Service – Multi-tenant Setup & Git Submodules