The file I’m working with is the Theme Development Checklist. It’s directly from WordPress.
“Theme Unit Test
This section correlates to a WordPress export (WXR) file that you can import into a WordPress installation to test your theme. Post titles in the test data correlate with section titles below.
Test Procedure
Download test data: https://svn.automattic.com/wpcom-themes/test-data.2008-12-22.xml
Import test data into your WordPress install. Do this by going to Tools -> Import.
Each “test” is a page or post described in the sections below.”
This file will not open. The message I keep getting is:
“Invalid file
Please upload a valid WXR (WordPress eXtended RSS) export file”