You better re-read what he said.
" they ask to upload the stl to a website with your email address, and you’ll receive a mail with the application & code".
They want to upload a STL to a website and presumably using his email and then he will get an email with “software” and the code. It is implied he would have to load the software to make the print and the code could be access to the STL or the software or worse, the email itself can easily be malicious.
How is he going to get the STL to upload if they don’t upload it to HUBS which it sounds like they are trying to circumvent? Why would they send it to him just to ask him to upload it to some website? Make no sense when they could do it themselves.
An email with software and code specifically implies you will download and install something and the code to run it or to actually download the STL they upload.