If you landed on ft-oscore.geo.opera.com, you probably saw nothing but a 404 error. That's because this subdomain, despite belonging to the Opera browser family, isn't a functioning website. It's almost certainly a backend endpoint or an abandoned test service that wasn't meant to face the public.
For someone wondering "is ft-oscore.geo.opera.com a scam?" the honest answer is that it's not a scam in the usual sense, but it's also not something you should trust with your data or your visit. The SSL certificate doesn't match the domain name, which means any data sent to this URL could be intercepted. There are no contact pages, no privacy policy, and no history in the Wayback Machine. These are all red flags for a site you'd rely on for anything.
Opera Software is a legitimate company, but that alone doesn't make every subdomain safe. Most companies have internal services that aren't meant for customers. The smart move is to avoid using this URL for anything and report the broken subdomain to Opera if you need access to geo-related functionality.