diff --git a/modules/libjar/nsIJARChannel.idl b/modules/libjar/nsIJARChannel.idl
index 0ecdf1df8654..aef430c68f41 100644
--- a/modules/libjar/nsIJARChannel.idl
+++ b/modules/libjar/nsIJARChannel.idl
@@ -39,13 +39,6 @@ interface nsIJARChannel : nsIChannel
      * For child process, set this to make sure that a valid file descriptor of
      * JAR file is always provided when calling NSPRFileDesc().
      * Must be set before Open() or AsyncOpen() to be effective.
-     *
-     * Note that the file descriptor returned by NSPRFileDesc() is duplicated
-     * from the original, which shares its file offset with the original.  If
-     * the file offset is modified (ex: by lseek/read/write) on one of the
-     * shared descriptors, the offset is also changed for the other.
-     * It can be safely used only with operations that take absolute offsets,
-     * such as mmap/pread/pwrite.
      */
     void ensureChildFd();
 };
diff --git a/netwerk/ipc/RemoteOpenFileChild.h b/netwerk/ipc/RemoteOpenFileChild.h
index c73adc22408d..808e1c73c30f 100644
--- a/netwerk/ipc/RemoteOpenFileChild.h
+++ b/netwerk/ipc/RemoteOpenFileChild.h
@@ -32,15 +32,13 @@ namespace net {
  *
  * To open a file handle with this class, AsyncRemoteFileOpen() must be called
  * first.  After the listener's OnRemoteFileOpenComplete() is called, if the
- * result is NS_OK, nsIFile.OpenNSPRFileDesc() may be called to get a
- * duplicated file descriptor.
+ * result is NS_OK, nsIFile.OpenNSPRFileDesc() may be called--once--to get the
+ * file handle.
  *
- * Note that the file descriptor returned by NSPRFileDesc() is duplicated from
- * the original, which shares its file offset with the original.  If the file
- * offset is modified (ex: by lseek/read/write) on one of the shared
- * descriptors, the offset is also changed for the other.   It can be safely
- * used only with operations that take absolute offsets, such as
- * mmap/pread/pwrite.
+ * Note that calling Clone() on this class results in the filehandle ownership
+ * being passed on to the new RemoteOpenFileChild. I.e. if
+ * OnRemoteFileOpenComplete is called and then Clone(), OpenNSPRFileDesc() will
+ * work in the cloned object, but not in the original.
  *
  * This class should only be instantiated in a child process.
  *