How upload HTML file to Files section (CDN)

Hello:

I understand that it is supposed that it is not possible to upload an HTML page to the files section of an store (basically only images and PDFs are allowed) but, I do not understand how another developer has been able to upload this html file:

https://cdn.shopify.com/s/files/1/0033/4807/0511/files/download.html (shows a white screen but has html code inside it)

It is an HTML file (format not allowed) and the url is linked to the Files section and the Shopify CDN. I have tried manually and with the GraphQL API and the message is always the same: “format not allowed”.

This is something that escapes me… How is this possible?

Any help will be appreciated!

Any luck finding info on this?

Also looking to do same