Got it. So in this case, some domain registrars will do masked URL loading for mobile versions of the site versus the desktop version. This is something I’d recommend touching base with your domain provider to discuss, as this isn’t something Squarespace provides.  

Taking a look at the domain for the site, it appears to be managed by Domain.com according to who.is registration records:  

Thus, I’d recommend reaching out to them to request this information. Squarespace does not automatically create this kind of masking, so you may want to clarify with your client what specific information they may be looking for, and direct them to the domain provider if needed.

Thanks!