firestore security rule Warning

[thanhtutzaw]

I found this in documentation

Note: The server client libraries bypass all Cloud Firestore Security Rules and instead authenticate through Google Application Default Credentials. If you are using the server client libraries or the REST or RPC APIs, make sure to set up Identity and Access Management (IAM) for Cloud Firestore.

What does it means exactly . My understanding is I have to manage the IAM in google cloud . I do not need to set rule in firestore . Right? I am asking here because , my project have receiving about unsecure firestore rules.