I have a rather unusual situation. We have a vendor that we use for generating documents we send to clients. The documents are built inside the software provided by the vendor. The vendor's software has version control but it's somewhat rudimentary. We still have to track requests for document creation and updates through Azure, but the changes and the original do not exist in azure. Although the software the vendor provides allows you to look at old and new versions (if you want to look at the version 1.1 and the 1.2 you can look at both), but provides no comparison tools. You simply have to look at both and compare. The documents themselves are XML files so what devs usually do is copy the old version and the new version and compare them in VS code, but this is obviously a bit slow and is manual.

The software has an API and I can access both versions of their changes through the version control API they provide. I want to be able to send both to azure and then compare them so that the review of the changes can be done inside azure. I know I can use a third party API in azure, but I'm not sure what the comparison would be. I want to be able to do something along the lines of a pull request allowing you to easily see the two versions of the XML side by side and show the changes. But I don't think you can do pull requests on files that aren't stored in Azure. Is there a way to achieve what I am looking for?