NordVPN, a VPN service provider, got hacked some time in 2018. In their official response, they say that only one server was affected due to an insecure remote management system left on the machine by the datacenter provider. Private keys got leaked (bad), some other VPN providers were also breached (bad) but that's not what I want to write about (good) because there are better places to read about it.
Behind the curtain, the VPN in the Opera browser is just a proxy. Here's how it works.