Environment detection algorithm for the guardian boundary setting.

Hello,

I have a question about the guardian boundary setting.

How the oculus save/remember the guardian boundary setting?
+ There should be a certain threshold that decides 'This environment was same as previous or not.'

I want to know how oculus compares the previous/current environment and judge whether they are identical or not.

Is there any open source/code/document related to this issue?

Thanks.