diff --git a/composer.json b/composer.json
index f0f23d18b6..b9fda4abe4 100644
--- a/composer.json
+++ b/composer.json
@@ -29,6 +29,10 @@
         "source": "https://github.com/PHPCSStandards/PHP_CodeSniffer",
         "security": "https://github.com/PHPCSStandards/PHP_CodeSniffer/security/policy"
     },
+    "suggest": {
+        "ext-iconv": "For accurate character length calculation when the checked files contain multi-byte characters.",
+        "ext-pcntl": "For parallel processing support via the --parallel CLI option."
+    },
     "require": {
         "php": ">=7.2.0",
         "ext-simplexml": "*",