When you start dealing with management groups in Azure, you may get to the point where you want to rename the “Root” management group. But even the simple query of the group will cause a problem.
In order for modifications/queries to be possible for this management group, you must first elevate the access rights for your own account, even if you are already a directory administrator. A corresponding message is also displayed in the Azure Portal.
The entire process is explained in the article “Elevate access to manage all Azure subscriptions and management Groups”. Once you have altered your own access rights as described here or had them altered, you can make the appropriate changes or simply query the management group.
Unfortunately, the “Tenant Root Group” cannot be queried by name in the Azure CLI resp. the name of this group is not meaningful. However, with elevated access rights you can query all management groups and thus find out the name of this particular group.
az account management-group list