--- /dev/null
+<?php
+
+namespace Drupal\libraries\ExternalLibrary\Definition;
+
+/**
+ * Provides an interface for library definition discoveries that are writable.
+ *
+ * @see \Drupal\libraries\ExternalLibrary\Definition\DefinitionDiscoveryInterface
+ * @see \Drupal\libraries\ExternalLibrary\Definition\ChainDefinitionDiscovery
+ */
+interface WritableDefinitionDiscoveryInterface extends DefinitionDiscoveryInterface {
+
+ /**
+ * Writes a library definition persistently.
+ *
+ * @param string $id
+ * The library ID.
+ * @param array $definition
+ * The library definition to write.
+ *
+ * @return $this
+ */
+ public function writeDefinition($id, $definition);
+
+}