The articles below make hardly disputable claims that Datamining company Tesonet owns and operates the VPN providers NordVPN and ProtonVPN, which at this present time are heavily promoted through the notification ads system. What is the opinion of Brave employees about the claims of this author? Would they want their name and their claim for privacy to be associated with unreliable VPN providers?
http://vpnscam.com/tesonet-data-mining-company-owns-nordvpn-protonmail-protonvpn/http://vpnscam.com/nordvpn-protonvpn-proton-mail-owned-by-tesonet-ceo-darius-bereika/
ProtonVPN just made significant portions of their code open source, so raking through that might settle some doubts. I can’t say I find this site entirely trustworthy with the typo (“rip off’s”) at the top of the page. English may not be their first language, but it definitely makes the site come across as amateurish. ProtonVPN also has their own subreddit, so you could also ask them directly.