Drupal Association members fund grants that make connections all over the world.
The current README states:
These files are use in some tests that upload files or other operations were
a file is useful. These files are copied to the files directory as specified
in the site settings. Other tests files are generated in order to save space.
Perhaps this might be better:
These files are useful in tests that upload files or otherwise need to manipulate files, in which case they are copied to the files directory as specified in the site settings. Dummy files can also be generated by tests in order to save space.