diff --git a/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties b/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
index 8666c34..7c9816c 100644
--- a/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
+++ b/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/internal/CLIText.properties
@@ -257,7 +257,7 @@
 usage_ReadDirCache= Read the DirCache 100 times
 usage_RebuildCommitGraph=Recreate a repository from another one's commit graph
 usage_RebuildRefTree=Copy references into a RefTree
-usage_RebuildRefTreeEnable=set extensions.refsStorage = reftree
+usage_RebuildRefTreeEnable=set extensions.refStorage = reftree
 usage_Remote=Manage set of tracked repositories
 usage_RepositoryToReadFrom=Repository to read from
 usage_RepositoryToReceiveInto=Repository to receive into
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/RebuildRefTree.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/RebuildRefTree.java
index 57345e2..8cde513 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/RebuildRefTree.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/RebuildRefTree.java
@@ -133,7 +133,7 @@
 			if (enable && !(db.getRefDatabase() instanceof RefTreeDatabase)) {
 				StoredConfig cfg = db.getConfig();
 				cfg.setInt("core", null, "repositoryformatversion", 1); //$NON-NLS-1$ //$NON-NLS-2$
-				cfg.setString("extensions", null, "refsStorage", "reftree"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+				cfg.setString("extensions", null, "refStorage", "reftree"); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 				cfg.save();
 				errw.println("Enabled reftree."); //$NON-NLS-1$
 				errw.flush();
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftree/LocalDiskRefTreeDatabaseTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftree/LocalDiskRefTreeDatabaseTest.java
index 67a7819..d5a07e0 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftree/LocalDiskRefTreeDatabaseTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftree/LocalDiskRefTreeDatabaseTest.java
@@ -83,7 +83,7 @@
 		FileRepository init = createWorkRepository();
 		FileBasedConfig cfg = init.getConfig();
 		cfg.setInt("core", null, "repositoryformatversion", 1);
-		cfg.setString("extensions", null, "refsStorage", "reftree");
+		cfg.setString("extensions", null, "refStorage", "reftree");
 		cfg.save();
 
 		repo = (FileRepository) new FileRepositoryBuilder()
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/LongMapTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/LongMapTest.java
similarity index 98%
rename from org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/LongMapTest.java
rename to org.eclipse.jgit.test/tst/org/eclipse/jgit/util/LongMapTest.java
index 1a86aaf..054c61e 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/LongMapTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/LongMapTest.java
@@ -41,7 +41,7 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.eclipse.jgit.transport;
+package org.eclipse.jgit.util;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/NBTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/NBTest.java
index 7e11a61..d2d44ff 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/NBTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/NBTest.java
@@ -90,6 +90,24 @@
 	}
 
 	@Test
+	public void testDecodeUInt24() {
+		assertEquals(0, NB.decodeUInt24(b(0, 0, 0), 0));
+		assertEquals(0, NB.decodeUInt24(padb(3, 0, 0, 0), 3));
+
+		assertEquals(3, NB.decodeUInt24(b(0, 0, 3), 0));
+		assertEquals(3, NB.decodeUInt24(padb(3, 0, 0, 3), 3));
+
+		assertEquals(0xcede03, NB.decodeUInt24(b(0xce, 0xde, 3), 0));
+		assertEquals(0xbade03, NB.decodeUInt24(padb(3, 0xba, 0xde, 3), 3));
+
+		assertEquals(0x03bade, NB.decodeUInt24(b(3, 0xba, 0xde), 0));
+		assertEquals(0x03bade, NB.decodeUInt24(padb(3, 3, 0xba, 0xde), 3));
+
+		assertEquals(0xffffff, NB.decodeUInt24(b(0xff, 0xff, 0xff), 0));
+		assertEquals(0xffffff, NB.decodeUInt24(padb(3, 0xff, 0xff, 0xff), 3));
+	}
+
+	@Test
 	public void testDecodeInt32() {
 		assertEquals(0, NB.decodeInt32(b(0, 0, 0, 0), 0));
 		assertEquals(0, NB.decodeInt32(padb(3, 0, 0, 0, 0), 3));
@@ -198,6 +216,39 @@
 	}
 
 	@Test
+	public void testEncodeInt24() {
+		byte[] out = new byte[16];
+
+		prepareOutput(out);
+		NB.encodeInt24(out, 0, 0);
+		assertOutput(b(0, 0, 0), out, 0);
+
+		prepareOutput(out);
+		NB.encodeInt24(out, 3, 0);
+		assertOutput(b(0, 0, 0), out, 3);
+
+		prepareOutput(out);
+		NB.encodeInt24(out, 0, 3);
+		assertOutput(b(0, 0, 3), out, 0);
+
+		prepareOutput(out);
+		NB.encodeInt24(out, 3, 3);
+		assertOutput(b(0, 0, 3), out, 3);
+
+		prepareOutput(out);
+		NB.encodeInt24(out, 0, 0xc0deac);
+		assertOutput(b(0xc0, 0xde, 0xac), out, 0);
+
+		prepareOutput(out);
+		NB.encodeInt24(out, 3, 0xbadeac);
+		assertOutput(b(0xba, 0xde, 0xac), out, 3);
+
+		prepareOutput(out);
+		NB.encodeInt24(out, 3, -1);
+		assertOutput(b(0xff, 0xff, 0xff), out, 3);
+	}
+
+	@Test
 	public void testEncodeInt32() {
 		final byte[] out = new byte[16];
 
@@ -315,10 +366,24 @@
 		return r;
 	}
 
+	private static byte[] b(int a, int b, int c) {
+		return new byte[] { (byte) a, (byte) b, (byte) c };
+	}
+
 	private static byte[] b(final int a, final int b, final int c, final int d) {
 		return new byte[] { (byte) a, (byte) b, (byte) c, (byte) d };
 	}
 
+	private static byte[] padb(int len, int a, int b, int c) {
+		final byte[] r = new byte[len + 4];
+		for (int i = 0; i < len; i++)
+			r[i] = (byte) 0xaf;
+		r[len] = (byte) a;
+		r[len + 1] = (byte) b;
+		r[len + 2] = (byte) c;
+		return r;
+	}
+
 	private static byte[] padb(final int len, final int a, final int b,
 			final int c, final int d) {
 		final byte[] r = new byte[len + 4];
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java
index 6a674aa..646feac 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/FileRepository.java
@@ -216,7 +216,7 @@
 				ConfigConstants.CONFIG_KEY_REPO_FORMAT_VERSION, 0);
 
 		String reftype = repoConfig.getString(
-				"extensions", null, "refsStorage"); //$NON-NLS-1$ //$NON-NLS-2$
+				"extensions", null, "refStorage"); //$NON-NLS-1$ //$NON-NLS-2$
 		if (repositoryFormatVersion >= 1 && reftype != null) {
 			if (StringUtils.equalsIgnoreCase(reftype, "reftree")) { //$NON-NLS-1$
 				refs = new RefTreeDatabase(this, new RefDirectory(this));
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java
index db3578b..2f6b271 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/PackParser.java
@@ -82,6 +82,7 @@
 import org.eclipse.jgit.lib.ProgressMonitor;
 import org.eclipse.jgit.util.BlockList;
 import org.eclipse.jgit.util.IO;
+import org.eclipse.jgit.util.LongMap;
 import org.eclipse.jgit.util.NB;
 import org.eclipse.jgit.util.sha1.SHA1;
 
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/LongMap.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/LongMap.java
similarity index 82%
rename from org.eclipse.jgit/src/org/eclipse/jgit/transport/LongMap.java
rename to org.eclipse.jgit/src/org/eclipse/jgit/util/LongMap.java
index 4d60202..7b0b0c7 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/LongMap.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/LongMap.java
@@ -41,15 +41,16 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-package org.eclipse.jgit.transport;
+package org.eclipse.jgit.util;
 
 /**
- * Simple Map<long,Object> helper for {@link PackParser}.
+ * Simple Map<long,Object>.
  *
  * @param <V>
  *            type of the value instance.
+ * @since 4.9
  */
-final class LongMap<V> {
+public class LongMap<V> {
 	private static final float LOAD_FACTOR = 0.75f;
 
 	private Node<V>[] table;
@@ -60,16 +61,27 @@
 	/** Next {@link #size} to trigger a {@link #grow()}. */
 	private int growAt;
 
-	LongMap() {
+	/** Initialize an empty LongMap. */
+	public LongMap() {
 		table = createArray(64);
 		growAt = (int) (table.length * LOAD_FACTOR);
 	}
 
-	boolean containsKey(final long key) {
+	/**
+	 * @param key
+	 *            the key to find.
+	 * @return {@code true} if {@code key} is present in the map.
+	 */
+	public boolean containsKey(long key) {
 		return get(key) != null;
 	}
 
-	V get(final long key) {
+	/**
+	 * @param key
+	 *            the key to find.
+	 * @return stored value of the key, or {@code null}.
+	 */
+	public V get(long key) {
 		for (Node<V> n = table[index(key)]; n != null; n = n.next) {
 			if (n.key == key)
 				return n.value;
@@ -77,7 +89,12 @@
 		return null;
 	}
 
-	V remove(final long key) {
+	/**
+	 * @param key
+	 *            key to remove from the map.
+	 * @return old value of the key, or {@code null}.
+	 */
+	public V remove(long key) {
 		Node<V> n = table[index(key)];
 		Node<V> prior = null;
 		while (n != null) {
@@ -95,7 +112,14 @@
 		return null;
 	}
 
-	V put(final long key, final V value) {
+	/**
+	 * @param key
+	 *            key to store {@code value} under.
+	 * @param value
+	 *            new value.
+	 * @return prior value, or null.
+	 */
+	public V put(long key, V value) {
 		for (Node<V> n = table[index(key)]; n != null; n = n.next) {
 			if (n.key == key) {
 				final V o = n.value;
@@ -145,9 +169,7 @@
 
 	private static class Node<V> {
 		final long key;
-
 		V value;
-
 		Node<V> next;
 
 		Node(final long k, final V v) {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java
index 8536f1d..471a499 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/NB.java
@@ -113,6 +113,24 @@
 	}
 
 	/**
+	 * Convert sequence of 3 bytes (network byte order) into unsigned value.
+	 *
+	 * @param intbuf
+	 *            buffer to acquire the 3 bytes of data from.
+	 * @param offset
+	 *            position within the buffer to begin reading from. This
+	 *            position and the next 2 bytes after it (for a total of 3
+	 *            bytes) will be read.
+	 * @return signed integer value that matches the 24 bits read.
+	 * @since 4.9
+	 */
+	public static int decodeUInt24(byte[] intbuf, int offset) {
+		int r = (intbuf[offset] & 0xff) << 8;
+		r |= intbuf[offset + 1] & 0xff;
+		return (r << 8) | (intbuf[offset + 2] & 0xff);
+	}
+
+	/**
 	 * Convert sequence of 4 bytes (network byte order) into signed value.
 	 *
 	 * @param intbuf
@@ -223,6 +241,29 @@
 	}
 
 	/**
+	 * Write a 24 bit integer as a sequence of 3 bytes (network byte order).
+	 *
+	 * @param intbuf
+	 *            buffer to write the 3 bytes of data into.
+	 * @param offset
+	 *            position within the buffer to begin writing to. This position
+	 *            and the next 2 bytes after it (for a total of 3 bytes) will be
+	 *            replaced.
+	 * @param v
+	 *            the value to write.
+	 * @since 4.9
+	 */
+	public static void encodeInt24(byte[] intbuf, int offset, int v) {
+		intbuf[offset + 2] = (byte) v;
+		v >>>= 8;
+
+		intbuf[offset + 1] = (byte) v;
+		v >>>= 8;
+
+		intbuf[offset] = (byte) v;
+	}
+
+	/**
 	 * Write a 32 bit integer as a sequence of 4 bytes (network byte order).
 	 *
 	 * @param intbuf