diff --git a/internal/manifest/manifest.go b/internal/manifest/manifest.go
index a0b5a3e0c..0a7c16c19 100644
--- a/internal/manifest/manifest.go
+++ b/internal/manifest/manifest.go
@@ -47,8 +47,33 @@ func (m *OSBuildManifest) UnmarshalJSON(payload []byte) error {
 	return nil
 }
 
+// Manifest represents a manifest initialised with all the information required
+// to generate the pipelines but no content. The content included in the
+// Content field must be resolved before serializing.
 type Manifest struct {
 	pipelines []Pipeline
+
+	// Content for the image that will be built by the Manifest. Each content
+	// type should be resolved before passing to the Serialize method.
+	Content Content
+}
+
+// Content for the image that will be built by the Manifest. Each content type
+// should be resolved before passing to the Serialize method.
+type Content struct {
+	// PackageSets are sequences of package sets, each set consisting of a list
+	// of package names to include and exclude and a set of repositories to use
+	// for resolving. Package set sequences (chains) should be depsolved in
+	// separately and the result combined. Package set sequences (chains) are
+	// keyed by the name of the Pipeline that will install them.
+	PackageSets map[string][]rpmmd.PackageSet
+
+	// Containers are source specifications for containers to embed in the image.
+	Containers []container.SourceSpec
+
+	// OSTreeCommits are source specifications for ostree commits to embed in
+	// the image or use as parent commits when building a new one.
+	OSTreeCommits []ostree.SourceSpec
 }
 
 func New() Manifest {