When an Authentication Connection is deleted, the main reference you will have for this is the EntityId. If you want to know which Authentication Connection was deleted, you can use this EntityId to look in the other audit tables that will have registered information on the object when inserted and updated.

[Table].[Column] storing log information Description of information stored
[AuditEvent].[EventType] Identifies the event by the value in this column being InsertApprovedConsents
[AuditEvent].[UTCTimestamp] Specifies the date and time in UTC that the event occurred.
[AuditEvent].[UserName] Saves the unique identity bearing claim in the Username column if this action is carried out via a federated user. The federated user might or might not exist in the Identify database; he will still be registered.
[AuditEvent].[ApplicationId] Stores the name of the service provider from where the deletion was made. This will either be the Identify*Admin site or the Identify*Service site.
[Tombstone].[EntityId] All claim records are identified by a unique identifier. This column registers this unique identifier in order to identify the specific user that the event in question occurred to.
[AuditApprovedConsent].[ProtocolConnectionId] Stores the ProtocolConnectionId where the Consent was approved.
[AuditApprovedConsent].[ProtocolConnectionName] Stores the ProtocolConnectionName where the Consent was approved.
[AuditApprovedConsent].[AuthenticationConnectionId] Stores the AuthenticationConnectionId where the Consent was approved.
[AuditApprovedConsent].[AuthenticationConnectionName] Stores the AuthenticationConnectionName where the Consent was approved.
[AuditApprovedConsent].[UserId] Identifies the UserId of the person who logged in and approved the Consent.
[AuditApprovedConsentItem].[ClaimSetId] Registers the unique identifier of the claim set, which is included in the Consent.
[AuditApprovedConsentItem].[Name] Registers the claim set name that is given to the claim set.
[AuditApprovedConsentItem].[IsApproved] Registers whether the claim set is approved or not.
[AuditApprovedConsentItem].[ClaimTypes] Registers the claim types that are given to the claim set.