Give Search2 backend its own YAML configuration file.

config/vufind/searchspecs2.yaml

+# This is the search configuration for the secondary search handler.
+# By default, it simply inherits rules from the parent handler.
+"@parent_yaml": "searchspecs.yaml"
\ No newline at end of file

module/VuFind/src/VuFind/Search/Factory/Search2BackendFactory.php

@@ -46,5 +46,6 @@ class Search2BackendFactory extends SolrDefaultBackendFactory
     {
         parent::__construct();
         $this->mainConfig = $this->searchConfig = $this->facetConfig = 'Search2';
+        $this->searchYaml = 'searchspecs2.yaml';
     }
 }