Current behavior: 
At the moment, our Completed file name and export path section of project settings allows to do changes like adding extra text or cut off some parts from the file name upon export as Completed file. A more specific changes like search and replace functions are not yet available. 

Requested behavior: 
Make it possible to search for a language code or name in the source file and replace it with target one. 

Use case:
It would be useful for clients who need to have the language code in all files and it is not often at the end or beginning of the file name.