Update 2020-04-29: Bug fix #29
Description
See
https://www.ladybug.tools/spider-gbxml-tools/spider-gbxml-viewer/dev/
The issue was that the script checked for the existence of the string "xmlns" - which points toward the namespace to be used - in the gbXML file and ignored the file if it did not exist.
In the dev release this line has been commented out. in any case all this indicates that there should be better error checking to make sure that we have a valid XML file and not a regular text or image file or whatever loaded by error.