This page is for manual testing of file-upload, specifically to test file-input element with the multiple-attribute set. Selenium doesn't support testing with the multiple-attribute.
However, automated Selenium test cases do test multiple file upload where there are multiple file-input elements within the same form (testing of this is supported by Selenium).
Uploaded files will be saved under: /tmp/UploaderRoot/upload-515370 (with their original names).