Primitives

Argo CD models the world as a small set of CRDs in pkg/apis/application/v1alpha1/. Every UI page, CLI subcommand, and reconciler ultimately reads or writes one of these.

Page	CRD / object
Application	argoproj.io/v1alpha1 Application — the unit of deployment.
AppProject	argoproj.io/v1alpha1 AppProject — multi-tenant boundary.
ApplicationSet	argoproj.io/v1alpha1 ApplicationSet — fan-out factory.
Cluster and repository secrets	Labelled Kubernetes Secrets that register destination clusters and source repos/credentials.

The CRDs themselves are generated from the Go types under pkg/apis/application/v1alpha1/:

• types.go — the bulk of the surface (Application, Operation, SyncPolicy, Source, Destination, …). Largest hand-written types file in the repo.
• app_project_types.go — AppProject and friends.
• applicationset_types.go — ApplicationSet and generator structs.
• repository_types.go — Repository, RepoCredentials.
• application_annotations.go, application_defaults.go, cluster_constants.go — string constants used across the codebase.
• generated.pb.go, openapi_generated.go, zz_generated.deepcopy.go — generated. Do not edit by hand.

After editing any of the hand-written files run make codegen to regenerate the artifacts.