I learned a decent bit about how biometric authentication works (or at least this specific implementation) by installing, setting up, and tweaking settings for Biopass. I also learned about how when you do first login using this method, it can fail to unlock keyrings because the password authentication has been bypassed so no password has been provided to unlock the keyring. It includes anti-spoofing local AI models, and the dev plans to have the option for the user to download and use any model for anti-spoofing/recognition. Interesting stuff.

https://github.com/TickLabVN/biopass