title: Best content-type and extension for web delivered Excel 2003 SpreadsheetML file
body: <p>I am working with an API that has a report URL call. The report has an "Excel 2003 XML" format option. When that is selected they deliver it as:</p>
  
  <pre><code>Content-Type: application/vnd.ms-excel
  content-disposition: inline; filename="report-name.xls"
  </code></pre>
  
  <p>OpenOffice.org up to 3.0 tries to bring this in as a text import and I'm concerned that Office 2007 might give users the extension mismatch warning. This shouldn't be our problem but people like to shoot the messenger so I am researching and looking for suggestions to give the API developers about file name extensions.</p>
  
  <p>I can rename the file to .xlsx or .xml and OOo happly opens the file into Calc, but the file isn't really an .xlsx file, .xml is annoyingly generic and I don't know what Office 2007 will think of those options.</p>
  
  <p>What is the best content-type and extension for web delivered Excel 2003 (11) SpreadsheetML files to avoid these and other issues?</p>