diff --git a/arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java b/arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java
index 021a20700..b1266e2b5 100644
--- a/arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java
+++ b/arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java
@@ -30,7 +30,6 @@
 package cc.arduino.contributions.libraries;
 
 import cc.arduino.Constants;
-import cc.arduino.contributions.libraries.filters.LibraryInstalledInsideCore;
 import cc.arduino.contributions.libraries.filters.TypePredicate;
 import cc.arduino.contributions.packages.ContributedPlatform;
 import com.fasterxml.jackson.databind.DeserializationFeature;
@@ -130,10 +129,13 @@ public class LibrariesIndexer {
       scanInstalledLibraries(folderDesc);
     }
 
-    installedLibraries.stream().filter(new TypePredicate("Contributed")).filter(new LibraryInstalledInsideCore()).forEach(userLibrary -> {
-      ContributedPlatform platform = BaseNoGui.indexer.getPlatformByFolder(userLibrary.getInstalledFolder());
-      userLibrary.setTypes(Collections.singletonList(platform.getCategory()));
-    });
+    installedLibraries.stream() //
+        .filter(new TypePredicate("Contributed")) //
+        .filter(l -> l.getLocation() == Location.CORE || l.getLocation() == Location.REFERENCED_CORE) //
+        .forEach(l -> {
+          ContributedPlatform platform = BaseNoGui.indexer.getPlatformByFolder(l.getInstalledFolder());
+          l.setTypes(Collections.singletonList(platform.getCategory()));
+        });
   }
 
   private void scanInstalledLibraries(UserLibraryFolder folderDesc) {
diff --git a/arduino-core/src/cc/arduino/contributions/libraries/filters/LibraryInstalledInsideCore.java b/arduino-core/src/cc/arduino/contributions/libraries/filters/LibraryInstalledInsideCore.java
deleted file mode 100644
index a19b3d2d1..000000000
--- a/arduino-core/src/cc/arduino/contributions/libraries/filters/LibraryInstalledInsideCore.java
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * This file is part of Arduino.
- *
- * Copyright 2015 Arduino LLC (http://www.arduino.cc/)
- *
- * Arduino is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- *
- * As a special exception, you may use this file as part of a free software
- * library without restriction.  Specifically, if other files instantiate
- * templates or use macros or inline functions from this file, or you compile
- * this file and link it with other files to produce an executable, this
- * file does not by itself cause the resulting executable to be covered by
- * the GNU General Public License.  This exception does not however
- * invalidate any other reasons why the executable file might be covered by
- * the GNU General Public License.
- */
-
-package cc.arduino.contributions.libraries.filters;
-
-import processing.app.BaseNoGui;
-import processing.app.packages.UserLibrary;
-
-import java.util.function.Predicate;
-
-public class LibraryInstalledInsideCore implements Predicate<UserLibrary> {
-
-  @Override
-  public boolean test(UserLibrary contributedLibrary) {
-    return BaseNoGui.indexer.isFolderInsidePlatform(contributedLibrary.getInstalledFolder());
-  }
-
-}
diff --git a/arduino-core/src/cc/arduino/contributions/packages/ContributionsIndexer.java b/arduino-core/src/cc/arduino/contributions/packages/ContributionsIndexer.java
index 5d6e6536f..607d2bfde 100644
--- a/arduino-core/src/cc/arduino/contributions/packages/ContributionsIndexer.java
+++ b/arduino-core/src/cc/arduino/contributions/packages/ContributionsIndexer.java
@@ -461,10 +461,6 @@ public class ContributionsIndexer {
     return index.getInstalledPlatforms();
   }
 
-  public boolean isFolderInsidePlatform(final File folder) {
-    return getPlatformByFolder(folder) != null;
-  }
-
   public ContributedPlatform getPlatformByFolder(final File folder) {
     Optional<ContributedPlatform> platformOptional = getInstalledPlatforms().stream().filter(contributedPlatform -> {
       assert contributedPlatform.getInstalledFolder() != null;