--- /dev/null
+<?php
+
+namespace Drupal\libraries\ExternalLibrary\Dependency;
+
+use Drupal\libraries\ExternalLibrary\LibraryInterface;
+
+/**
+ * Provides an interface for libraries that depend on other libraries.
+ *
+ * @todo Implement versioned dependencies.
+ */
+interface DependentLibraryInterface extends LibraryInterface {
+
+ /**
+ * Returns the libraries dependencies, if any.
+ *
+ * @return string[]
+ * An array of library IDs of libraries that the library depends on.
+ */
+ public function getDependencies();
+
+}