Security: How to use fingerprint authentication to unlock the screen after restarting?

Android has a security feature that requires the user to enter a PIN / Pattern / Password, if an application locks the device using the Device administrator permission, or, when the device restarts.

Recently, however, I started using custom ROMs like LineageOS and Resurrection Remix. I noticed something interesting in Resurrection Remix: it allows you to use the fingerprint even after an administrator locks the device or restarts it. Take a look at the screenshot below.


You will find this configuration normally low Settings> Customizations> Interfaces> Fingerprint settings.

Now, with that option enabled, it allows me to unlock the device with fingerprint authentication, regardless of the method with which the device was previously blocked.

Since then I switched to LineageOS for reasons, but I want this feature and I am looking for help. I've also taken a look at sources of resurrection remixes, but I could not find anything useful.

Maybe, maybe, there's a build.prop` Will I be able to use the hack / tweak / option to obtain this feature in LineageOS as well?

Note: before someone points out, I understand that this option, if enabled, can seriously minimize the security of my device, but I want to know why it works how it works. I do not necessarily plan to enable this, but learning is always interesting. I also understand the code a bit, so feel free to use the code instances to clarify things.