diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftree/RefTreeDatabaseTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftree/RefTreeDatabaseTest.java
index 020d1b1b5..1bacfe46f 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftree/RefTreeDatabaseTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftree/RefTreeDatabaseTest.java
@@ -124,6 +124,17 @@ public void testGetRefs_EmptyDatabase() throws IOException {
 		assertTrue("no references", refdb.getRefs(ALL).isEmpty());
 		assertTrue("no references", refdb.getRefs(R_HEADS).isEmpty());
 		assertTrue("no references", refdb.getRefs(R_TAGS).isEmpty());
+		assertTrue("no references", refdb.getAdditionalRefs().isEmpty());
+	}
+
+	@Test
+	public void testGetAdditionalRefs() throws IOException {
+		update("refs/heads/master", A);
+
+		List<Ref> addl = refdb.getAdditionalRefs();
+		assertEquals(1, addl.size());
+		assertEquals("refs/txn/committed", addl.get(0).getName());
+		assertEquals(getTxnCommitted(), addl.get(0).getObjectId());
 	}
 
 	@Test
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollector.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollector.java
index 784507d88..33be3b15a 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollector.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsGarbageCollector.java
@@ -194,7 +194,7 @@ public boolean pack(ProgressMonitor pm) throws IOException {
 			refdb.refresh();
 			objdb.clearCache();
 
-			Collection<Ref> refsBefore = RefTreeNames.allRefs(refdb);
+			Collection<Ref> refsBefore = getAllRefs();
 			packsBefore = packsToRebuild();
 			if (packsBefore.isEmpty())
 				return true;
@@ -235,6 +235,18 @@ else if (RefTreeNames.isRefTree(refdb, ref.getName()))
 		}
 	}
 
+	private Collection<Ref> getAllRefs() throws IOException {
+		Collection<Ref> refs = refdb.getRefs(RefDatabase.ALL).values();
+		List<Ref> addl = refdb.getAdditionalRefs();
+		if (!addl.isEmpty()) {
+			List<Ref> all = new ArrayList<>(refs.size() + addl.size());
+			all.addAll(refs);
+			all.addAll(addl);
+			return all;
+		}
+		return refs;
+	}
+
 	private List<DfsPackFile> packsToRebuild() throws IOException {
 		DfsPackFile[] packs = objdb.getPacks();
 		List<DfsPackFile> out = new ArrayList<DfsPackFile>(packs.length);
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
index 2ce0d4734..49f9335ae 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java
@@ -629,15 +629,16 @@ private Set<ObjectId> listRefLogObjects(Ref ref, long minTime) throws IOExceptio
 	}
 
 	/**
-	 * Returns a map of all refs and additional refs (e.g. FETCH_HEAD,
+	 * Returns a collection of all refs and additional refs (e.g. FETCH_HEAD,
 	 * MERGE_HEAD, ...)
 	 *
-	 * @return a map where names of refs point to ref objects
+	 * @return a collection of refs pointing to live objects.
 	 * @throws IOException
 	 */
 	private Collection<Ref> getAllRefs() throws IOException {
-		Collection<Ref> refs = RefTreeNames.allRefs(repo.getRefDatabase());
-		List<Ref> addl = repo.getRefDatabase().getAdditionalRefs();
+		RefDatabase refdb = repo.getRefDatabase();
+		Collection<Ref> refs = refdb.getRefs(RefDatabase.ALL).values();
+		List<Ref> addl = refdb.getAdditionalRefs();
 		if (!addl.isEmpty()) {
 			List<Ref> all = new ArrayList<>(refs.size() + addl.size());
 			all.addAll(refs);
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftree/RefTreeDatabase.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftree/RefTreeDatabase.java
index dc6031110..f6fdef1fa 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftree/RefTreeDatabase.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftree/RefTreeDatabase.java
@@ -47,6 +47,8 @@
 import static org.eclipse.jgit.lib.Ref.Storage.PACKED;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -250,7 +252,23 @@ private static ObjectId idOf(@Nullable Ref src) {
 
 	@Override
 	public List<Ref> getAdditionalRefs() throws IOException {
-		return Collections.emptyList();
+		Collection<Ref> txnRefs;
+		if (txnNamespace != null) {
+			txnRefs = bootstrap.getRefs(txnNamespace).values();
+		} else {
+			Ref r = bootstrap.exactRef(txnCommitted);
+			if (r != null && r.getObjectId() != null) {
+				txnRefs = Collections.singleton(r);
+			} else {
+				txnRefs = Collections.emptyList();
+			}
+		}
+
+		List<Ref> otherRefs = bootstrap.getAdditionalRefs();
+		List<Ref> all = new ArrayList<>(txnRefs.size() + otherRefs.size());
+		all.addAll(txnRefs);
+		all.addAll(otherRefs);
+		return all;
 	}
 
 	@Override
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftree/RefTreeNames.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftree/RefTreeNames.java
index 239a74527..c53d6deb2 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftree/RefTreeNames.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftree/RefTreeNames.java
@@ -43,14 +43,6 @@
 
 package org.eclipse.jgit.internal.storage.reftree;
 
-import static org.eclipse.jgit.lib.RefDatabase.ALL;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
-
-import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.RefDatabase;
 
 /** Magic reference name logic for RefTrees. */
@@ -92,33 +84,6 @@ public static boolean isRefTree(RefDatabase refdb, String ref) {
 		return false;
 	}
 
-	/**
-	 * Snapshot all references from a RefTreeDatabase and its bootstrap.
-	 * <p>
-	 * There may be name conflicts with multiple {@link Ref} objects containing
-	 * the same name in the returned collection.
-	 *
-	 * @param refdb
-	 *            database instance.
-	 * @return all known references.
-	 * @throws IOException
-	 *             references cannot be enumerated.
-	 */
-	public static Collection<Ref> allRefs(RefDatabase refdb)
-			throws IOException {
-		Collection<Ref> refs = refdb.getRefs(ALL).values();
-		if (!(refdb instanceof RefTreeDatabase)) {
-			return refs;
-		}
-
-		RefDatabase bootstrap = ((RefTreeDatabase) refdb).getBootstrap();
-		Collection<Ref> br = bootstrap.getRefs(ALL).values();
-		List<Ref> all = new ArrayList<>(refs.size() + br.size());
-		all.addAll(refs);
-		all.addAll(br);
-		return all;
-	}
-
 	private RefTreeNames() {
 	}
 }