2) Refactor App->config[] into Core\PConfig

src/Core/Config/JITPConfigAdapter.php

@@ -28,7 +28,7 @@ class JITPConfigAdapter implements IPConfigAdapter
 			}
 		} else if ($cat != 'config') {
 			// Negative caching
-			PConfig::setPConfigValue($uid, $cat, "!<unset>!");
+			PConfig::setPConfigValue($uid, $cat, null, "!<unset>!");
 		}
 		DBA::close($pconfigs);
 	}

src/Core/PConfig.php

@@ -203,7 +203,11 @@ class PConfig extends BaseObject
 			self::$config[$uid][$cat] = [];
 		}
 
-		self::$config[$uid][$cat][$k] = $value;
+		if ($k === null) {
+			self::$config[$uid][$cat] = $value;
+		} else {
+			self::$config[$uid][$cat][$k] = $value;
+		}
 	}
 
 	/**