Misterious DefaultSPGroupsSiteMaster Feature

Question

In SharePoint Online and SharePoint 2019, as part of the Modern Team site, there is a DefaultSPGroupsSiteMaster Web feature with the ID d5a4ed08-27b9-4142-9804-45dec6fda126. This feature does not exist even in SharePoint 2019.

Does anyone know what this feature is supposed to do? I could not find any documentation describing it. I have checked if this feature eixsted as part of a classic Team site and it it's not present there. So I am curious what this does exactly.

This is how I have retrieved this feature:

Get-PnPFeature -Scope Web 

Answer 1

DefaultSPGroupsSiteMaster (e233eb34-e720-4ff9-9f53-a5aabc706d12) is a Hidden feature first introduced in SharePoint Online circa 2018. It was then added to SharePoint 2019 as well.

This feature is very lightweight and only does the following:

1. Ensure Visitos, Members and Owners SP Groups are created and contain a group owner.
2. Assign permissions to these groups.
3. Add a web property vti_createdassociatedgroups that contains principal IDs for the SP groups mentioned above.

The feature activation code is located in the Microsoft.SharePoint.dll (SP 2019 version), in the DefaultSPGroupsSiteMasterFeatureReceiver class.