Okay, found the error. When you right click on the link to the filename
to download the linked contents from the page I linked, what you
actually get is the code for the GitHub page which displays the code,
not the file itself. To get the file, and just the file, you need to
click through the link and then download using the "Raw" button (either
with a right click to save the linked contents or by following the link
and then saving the file once it's displayed by your browser). Download
the file in that way and it should work.