How can I add a special character to a URL page or link to a text file?

Hello,

I am applying for a developer API. One of the steps required for verification is that I need this file to be accessible at this exact URL, which has both a period as well as a double slash instead of single slash in it. However, it appears Squarespace does not allow special characters except hyphens at the end of the URL. How can I get around this problem?

Thank you!
-Don