We've found that files that are imported into the translation files of an Item do not get removed when the Item gets revised and new translation files are generated.
In the use case we've found the issue in, PDFs migrated through the DTU are not getting replaced when new translation files are generated. It's understandable that people could want to add files that stay with the item.

I propose that any file type in the translation files are always gets replaced as a new file of that type gets generated, as translation files should be an up to date translation of the item. If a file needs to stay as it is with the item then a specification type should be used.
Understanding that this could impact companies already using the translation files to keep files with the item, having a tenant property to toggle this replacement behavior would probably be best.