diff --git a/gen_pc_sidecar.php b/gen_pc_sidecar.php
index a5a9b1b..dbdc18e 100755
--- a/gen_pc_sidecar.php
+++ b/gen_pc_sidecar.php
@@ -15,7 +15,7 @@ $TARGET_EXTENSIONS = read_config_json("target_extensions");
 $LIST_FILTER_TYPE = read_config_json_string("list_filter_type");
 $EXTENSION_FILTER_LIST = read_config_json("extension_filter_list");
 $BLACKLISTED_TERMS = read_config_json("blacklisted_terms");
-$PREPEND_EXTENSIONS = read_config_json("prepend_extensions");
+$PREPEND_EXTENSIONS = read_config_json_object_list("prepend_extensions");
 
 function main(): void {
   global $TARGET_EXTENSIONS;
@@ -171,20 +171,12 @@ function pull_mac_list(): array {
 
 
 function read_config_json_file($path){
-    if (!is_file($path)) {
-        throw new RuntimeException("Config file not found: {$path}");
-    }
+    $json = file_get_contents($path);
+    $data = json_decode($json, true);
 
-    $raw = file_get_contents($path);
-    if ($raw === false) {
-        throw new RuntimeException("Unable to read config file: {$path}");
+    if ($data === null && json_last_error() !== JSON_ERROR_NONE) {
+        throw new RuntimeException("JSON decode error: " . json_last_error_msg());
     }
-
-    $data = json_decode($raw, true);
-    if (!is_array($data)) {
-        throw new RuntimeException("Invalid JSON in config file: {$path}");
-    }
-
     return $data;
 }
 
@@ -216,6 +208,23 @@ function read_config_json_string($key) {
     return strtolower(trim((string)$value));
 }
 
+function read_config_json_object_list($key) {
+    global $CONFIG;
+    $value = $CONFIG[$key] ?? [];
+
+    if (!is_array($value)) return [];
+
+    $out = [];
+    foreach ($value as $row) {
+        if (is_array($row) && isset($row['name'], $row['extension'])) {
+            $out[] = [
+                'name' => (string)$row['name'],
+                'extension' => (string)$row['extension'],
+            ];
+        }
+    }
+    return $out;
+}
 
 function pull_xml_file($file): DOMDocument {
   if (!file_exists($file)) {