diff --git src/js/_enqueues/admin/common.js src/js/_enqueues/admin/common.js
index 58f68d1..88924bf 100644
--- src/js/_enqueues/admin/common.js
+++ src/js/_enqueues/admin/common.js
@@ -19,6 +19,34 @@
 		__ = wp.i18n.__;
 
 /**
+ * @param {string} getter      The getter that was called.
+ * @param {string} version     The version of WordPress that deprecated the function.
+ * @param {string} replacement Optional. The getter that should have been called. Default null.
+ */
+function deprecatedGetter( getter, version, replacement ) {
+	if ( typeof replacement !== 'undefined' ) {
+		console.error( getter + ' is deprecated since version ' + version + '! Use ' + replacement + ' instead.' );
+	} else {
+		console.error( getter + ' is deprecated since version ' + version + ' with no alternative available.' );
+	}
+}
+
+/**
+ * Removed in 5.5.0, needed for back-compatibility.
+ *
+ * @since 2.6.0
+ * @deprecated 5.5.0
+ */
+window.commonL10n = {};
+
+[ 'warnDelete', 'dismiss', 'collapseMenu', 'expandMenu' ].forEach( function( getter ) {
+	window.commonL10n.__defineGetter__( getter, function() {
+		deprecatedGetter( getter, '5.5', 'wp.i18n' );
+		return '';
+	} );
+} );
+
+/**
  * Removed in 3.3.0, needed for back-compatibility.
  *
  * @since 2.7.0