Site Collection App Catalogs (SCAC) are much appreciated, thank you, Office 365 Team. Here is a couple of tips and tricks for SCAC.
Tip #1 You don’t need Tenant Admin rights to add a new Site Collection App Catalog
I have seen many blogs, forum threads etc that state that only Global Tenant Administrators can add new Site Collection App Catalogs. The truth is that a SharePoint Admin rights are enough. The trick is to make that SharePoint Admin Account to a site collection administrator of the app catalog site. To be precise the account that adds a new SCAC must have Manage Web Permissions, as stated in error message:
Add-SPOSiteCollectionAppCatalog : Must have Manage Web Site permissions or be a tenant admin in order to add or remove sites from the site collection app catalog allow list
Tip #2 List all Site Collection App Catalogs
To list all the SCACs in your tenant navigate to that url:
The official MSDocs state (2019-08-26):
Currently, it’s not possible to list all site collections in the tenant that have the site collection app catalog enabled.
The fun fact was that I sherlocked it since I knew my account needed access to the main App Catalog site. So there must be some information that is stored. How is it done a là SharePoint - yes, it is stored in a hidden list. Like in the olden days. 🧐