Account activity in google tag manager displays information about the activities that have been done in the account. It is useful to determine which user has done a certain activity and when it was done.
For example, you created a container a month ago and after sometime another user deleted it. You might be wondering where the container is disappeared. So you can check in the account activity for the recent activities and the date it has been done.
Here is how to view account activity in google tag manager.
step#1: login to your tag manager account.
step#2: In the accounts section you will see the list of accounts you have created.
step#3: navigate to the specific account and click the verticle dotted line on top right of the account.
step#4: select account activity.
Inside you will see the list of activities done on the account.