--- /dev/null
+package org.argeo.api.gcr;
+
+import java.io.Serializable;
+import java.util.Set;
+
+public interface ContentMetadata extends Serializable {
+ Set<String> getKnownKeys();
+
+ Set<String> getTypes();
+
+ /** Whether that content can have unknown keys. */
+ default boolean isStructured() {
+ return false;
+ }
+}