Explanation

Git has a feature to override the display email and name even in old commits. It's called the .mailmap file, and in recent versions of git it is enabled by default when viewing git log. This .mailmap file is useful for avoiding having to rewrite history in git when someone changes their name, such as when getting married, transitioning gender, or replacing their single-word glam name with "The Artist Formerly Known As GlamName".

Suggestion

In the main branch of a repo, if the latest commit has a .mailmap at the root, apply that in all display contexts.

But there's an existing feature for this, isn't there?

Each user in Bitbucket can set their alternative email addresses to correlate old commits with their active Atlassian account. Unfortunately, the user-level configuration for alternative email addresses requires that an email can be verified. It is often that old commits have "email addresses" that are computer names, or email addresses that belong to defunct domains, or just dead email addresses. Without .mailmap functionality, these display identities cannot be correlated with an active Atlassian user.