python-3.6.zip added from Github

README.cosmo contains the necessary links.

third_party/python/Lib/idlelib/rstrip.py

@@ -0,0 +1,29 @@
+'Provides "Strip trailing whitespace" under the "Format" menu.'
+
+class Rstrip:
+
+    def __init__(self, editwin):
+        self.editwin = editwin
+
+    def do_rstrip(self, event=None):
+
+        text = self.editwin.text
+        undo = self.editwin.undo
+
+        undo.undo_block_start()
+
+        end_line = int(float(text.index('end')))
+        for cur in range(1, end_line):
+            txt = text.get('%i.0' % cur, '%i.end' % cur)
+            raw = len(txt)
+            cut = len(txt.rstrip())
+            # Since text.delete() marks file as changed, even if not,
+            # only call it when needed to actually delete something.
+            if cut < raw:
+                text.delete('%i.%i' % (cur, cut), '%i.end' % cur)
+
+        undo.undo_block_stop()
+
+if __name__ == "__main__":
+    from unittest import main
+    main('idlelib.idle_test.test_rstrip', verbosity=2,)