Squashing the 2 commits into one:

FeatureFlags (for "skip non-explicit groups")

A local mod that skips non-explicit groups when the corresponding flag is defined.

Author: landreev

src/main/java/edu/harvard/iq/dataverse/search/SolrSearchServiceBean.java

@@ -1048,7 +1048,14 @@ private String getPermissionFilterQuery(DataverseRequest dataverseRequest, SolrQ
         for (Group group : groups) {
             String groupAlias = group.getAlias();
             if (groupAlias != null && !groupAlias.isEmpty() && (!avoidJoin || !groupAlias.startsWith("builtIn"))) {
-                groupList.add(IndexServiceBean.getGroupPrefix() + groupAlias);
+                boolean skipThisGroup = false;
+                if (FeatureFlags.SKIP_NONEXPLICIT_GROUPS.enabled() && group.getGroupProvider() != null && !"explicit".equals(group.getGroupProvider().getGroupProviderAlias())) {
+                    skipThisGroup = true;
+                    logger.info("Skipping non-explicit group " + groupAlias);
+                }
+                if (!skipThisGroup) {
+                    groupList.add(IndexServiceBean.getGroupPrefix() + groupAlias);
+                }
             }
         }
 

src/main/java/edu/harvard/iq/dataverse/settings/FeatureFlags.java

@@ -120,6 +120,7 @@ public enum FeatureFlags {
      * @since Dataverse 6.3
      */
     ADD_PUBLICOBJECT_SOLR_FIELD("add-publicobject-solr-field"),
+    SKIP_NONEXPLICIT_GROUPS("skip-nonexplicit-groups"),
     /**
      * With this flag set, Dataverse will index the actual origin of harvested
      * metadata records, instead of the "Harvested" string in all cases.