We need to plan how to migrate from old exceptions into custom named ones.

src/Libs/Exceptions/Backends/BackendException.php

@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace App\Libs\Exceptions;
+namespace App\Libs\Exceptions\Backends;
 
 use ErrorException;
 

src/Libs/Exceptions/Backends/InvalidArgumentException.php

@@ -2,12 +2,10 @@
 
 declare(strict_types=1);
 
-namespace App\Libs\Exceptions;
+namespace App\Libs\Exceptions\Backends;
 
 /**
  * Class InvalidArgumentException
- *
- * This class represents an exception that is thrown by the backend logic.
  */
 class InvalidArgumentException extends BackendException
 {

src/Libs/Exceptions/Backends/RuntimeException.php

@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Libs\Exceptions\Backends;
+
+/**
+ * Class RuntimeException
+ */
+class RuntimeException extends BackendException
+{
+}

src/Libs/Exceptions/RuntimeException.php

@@ -5,10 +5,8 @@ declare(strict_types=1);
 namespace App\Libs\Exceptions;
 
 /**
- * Class RuntimeException
- *
- * This class represents an exception that is thrown by the backend logic.
+ * General runtime exception.
  */
-class RuntimeException extends BackendException
+class RuntimeException extends \RuntimeException
 {
 }