diff --git a/src/Type/Php/ImplodeFunctionReturnTypeExtension.php b/src/Type/Php/ImplodeFunctionReturnTypeExtension.php
index 478eb9613b..679911891c 100644
--- a/src/Type/Php/ImplodeFunctionReturnTypeExtension.php
+++ b/src/Type/Php/ImplodeFunctionReturnTypeExtension.php
@@ -70,6 +70,7 @@ private function implode(Type $arrayType, Type $separatorType): Type
 			}
 		}
 
+		// implode is one of the four functions that can produce literal strings as blessed by the original RFC: wiki.php.net/rfc/is_literal
 		if ($arrayType->getIterableValueType()->isLiteralString()->yes() && $separatorType->isLiteralString()->yes()) {
 			$accessoryTypes[] = new AccessoryLiteralStringType();
 		}