Index: /trunk/src/org/openstreetmap/josm/io/MirroredInputStream.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/MirroredInputStream.java	(revision 6072)
+++ /trunk/src/org/openstreetmap/josm/io/MirroredInputStream.java	(revision 6073)
@@ -259,6 +259,12 @@
      * <p>
      * This can causes problems when downloading from certain GitHub URLs.
+     * 
+     * @param downloadUrl The resource URL to download
+     * @return The HTTP connection effectively linked to the resource, after all potential redirections
+     * @throws MalformedURLException If a redirected URL is wrong
+     * @throws IOException If any I/O operation goes wrong
+     * @since 6073
      */
-    protected HttpURLConnection connectFollowingRedirect(URL downloadUrl) throws MalformedURLException, IOException {
+    public static HttpURLConnection connectFollowingRedirect(URL downloadUrl) throws MalformedURLException, IOException {
         HttpURLConnection con = null;
         int numRedirects = 0;
Index: /trunk/src/org/openstreetmap/josm/plugins/PluginDownloadTask.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/plugins/PluginDownloadTask.java	(revision 6072)
+++ /trunk/src/org/openstreetmap/josm/plugins/PluginDownloadTask.java	(revision 6073)
@@ -22,4 +22,5 @@
 import org.openstreetmap.josm.gui.progress.NullProgressMonitor;
 import org.openstreetmap.josm.gui.progress.ProgressMonitor;
+import org.openstreetmap.josm.io.MirroredInputStream;
 import org.openstreetmap.josm.tools.CheckParameterUtil;
 import org.openstreetmap.josm.tools.Utils;
@@ -119,7 +120,5 @@
             URL url = new URL(pi.downloadlink);
             synchronized(this) {
-                downloadConnection = Utils.openHttpConnection(url);
-                downloadConnection.setRequestProperty("Cache-Control", "no-cache");
-                downloadConnection.connect();
+                downloadConnection = MirroredInputStream.connectFollowingRedirect(url);
             }
             in = downloadConnection.getInputStream();