If you receive an automated email from AssetAccountant with the description "Received request to attach an external identity with your account", this are typically sent when a user chooses to connect to an external Identity provider (eg Intuit, Xero or Microsoft) in order to login to AssetAccountant.
The messages tend to be relatively devoid of content for security purposes (I.e we won't disclose which provider over email), we'll simply send an alert to the user to ensure that this was a deliberate act on their behalf.