So I have no idea why this is not working.
I followed this lecture and made sure the .gitignore file was in the battletank folder.
Now I went to sourcetree and staged the files, from which Ben said the intermediate files would disappear.
But they don’t.
I committed the ignore file changes, made sure it was a gitignore file.
The context of the file is exactly the same as Ben’s…
How to fix this?