Einstein Activity Capture Audit Log entries

The Einstein Activity Capture setting "Activity Sharing with Non-Einstein Activity Capture Users" allows users who do not use Einstein Activity Capture see captured email and events.

If an EAC User shares a captured activity with everyone and this setting is enabled, then non-EAC Users are able to view the captured email or event.

When the non-EAC user views the captured activity, Salesforce internally provisions a "read-only EAC user" for that Salesforce user. This is needed due to the internal architecture or EAC. This action doesn't fully enable EAC for the user, or take up any EAC licenses. The user still cannot connect their own email accounts, none of their own email/calendar is captured. This "read-only EAC user" can only view captured activities that are shared with everyone.
 

Because a "read-only EAC user" was provisioned, that creates the audit message "Enabled Inbox for user: XYZ"
 

The audit message "Enabled Inbox for user: XYZ"is generated for 3 very different cases:

1. A user is assigned to Inbox.

2. A full EAC user is provisioned (by assigning the user to an EAC configuration).

3. A read-only EAC user is auto-created (under the hood), when the user views a captured activity.