diff --git a/docs/extension.schema.json b/docs/extension.schema.json
index d1b982c519d..b52369f8924 100644
--- a/docs/extension.schema.json
+++ b/docs/extension.schema.json
@@ -542,6 +542,10 @@
 			"type": "object",
 			"description": "Flags (letter symbols) shown on RecentChanges pages"
 		},
+		"MediaHandlers": {
+			"type": "object",
+			"description": "Plugins for media file type handling. Each entry in the array maps a MIME type to a PHP class name."
+		},
 		"ExtensionFunctions": {
 			"type": [
 				"array",
diff --git a/includes/registration/ExtensionProcessor.php b/includes/registration/ExtensionProcessor.php
index a5349fb4ac9..561e798fe31 100644
--- a/includes/registration/ExtensionProcessor.php
+++ b/includes/registration/ExtensionProcessor.php
@@ -26,6 +26,7 @@ class ExtensionProcessor implements Processor {
 		'RateLimits',
 		'ParserTestFiles',
 		'RecentChangesFlags',
+		'MediaHandlers',
 		'ExtensionFunctions',
 		'ExtensionEntryPointListFiles',
 		'SpecialPages',