Sun ODF Plug in 1.0 for Microsoft Office

The Sun ODF Plug in 1.0 for Microsoft Office gives users of Microsoft Word, Excel and Powerpoint the ability to read, edit and save to the ISO-standard Open Document Format (ODF = Open Document Format). I originally planned to list it as Open Source here. But, it looks like it is closed source. Its download page does not link to its source code just a binary EXE file. I find this kind of ironic (closed source for an open format).