https://www.bleepingcomputer.com/news/security/protonvpn-apps-open-sourced-for-added-transparency-and-security/

The code for ProtonVPN apps on all supported platforms - Android, iOS, macOS, and Windows - is now open source, the maker announces today, a move that follows a security audit from an independent party.

The decision distances the service from all the other options on the market and is in line with the company's belief in ethics, transparency, and security as core values for a trusted VPN (virtual private network) provider.