Let us say there is a project A, and i came across a project EA which extends the project. The problem is project A is not available under version control, it is only available as tarball releases.
The project EA extends A by creating a new github repository and adding new functionality, most of the changes are concentrated in a new subfolder but some rare changes exist in original code of A as well.
Now there is a version 2 tarball release for project A and i want to implement the same extension of EA for the new version.
What is the best gitflow for doing this? If the developer of EA had used submodules i could have just added that, but as is, he is making some changes (Albeit rarely) in the original code (From project A).
I am new to vcs but have read up on the basics of git and submodules, but the only way i can see doing this is create a separate repo, merge changes from EA and manually manage changes whenever EA is changed by it's developer.