Azure Static Web App : Logic behind default domain name partition id

Dear all,

I’m looking for clarification regarding Azure Static Web Apps hostname partitioning and Private Endpoint DNS behavior.

We noticed that Static Web Apps can receive default hostnames such as:

textCopy
myapp.azurestaticapps.net

or

textCopy
myapp.3.azurestaticapps.net

From the Private Endpoint documentation , it appears that the numeric segment (3 in this example) represents a partition/scale unit/stamp identifier, and that the corresponding Private DNS zone must match this value, for example:

textCopy
privatelink.3.azurestaticapps.net

We would like to better understand the underlying platform behavior because this has architectural implications for automation and DNS governance in enterprise environments.

1. What exactly does the partition ID / stamp represent in Azure Static Web Apps?
2. When does the default domain name contain a partition id ?
3. Is there a finite or published list of possible partition IDs?

Thanks in advance for your help