As a mod, I can head over to a user's profile page & look up info on their account history - login/logout dates, suspension dates, change in display names and so on.
However, if a user changes their display name from another Stack Exchange account (example: Stack Overflow) and copies them to all other network sites, then the change in display name is not recorded in the other sites.
For instance, I changed my display name from Sathya to sathyabh.at from my Stack Overflow user page & opted to copy this to all accounts.
However, this is not reflected in my Super User account history.
Note that the change in name from Sathya to sathyabh.at is not recorded. I reverted the change from Super User, and that is recorded.