On the Mac, Safari and Chrome store passwords in a key chain. To reveal any of those passwords you have to re-enter your macOS login password or whatever authentication method was used to log into the device (fingerprint, face ID, ...).

So it's not the program that is authenticated. The system simply makes sure that any program accessing that particularly sensitive data is really controlled by the logged in user.

This is entirely separate from protections for other files that may or may not be encrypted.