We work in the Compliance space, that requires us to track users who made changes to a document. We also have an Add-in that utilizes insertfilefrombase64 method to insert/replace content in our documents. When we use this method, the user is getting tracked as "Unknown" thus failing to track the user who made such changes. Requesting that this be changed and updated to track the user. If the same was done manually, the change is reflected against the user. 

a relevant bug was raised which was marked as an dev enhancement request by the team. 

https://github.com/OfficeDev/office-js/issues/5472