blazor server side – Why is Azure creating an appsettings.Production.json file?

I have no appsettings.production.json file in my application (I might have once had it but if so, it was deleted months ago).

In tracking down an unexpected environment property setting I discovered that in my dev slot there’s an appsettings.production.json, with about 40 properties set in it. It appears to be a copy of my appsettings.json from about a month ago.

How does this happen? And how do I get rid of it? The file does not exist in my GitHub. My code is pushed up to Azure by a GitHub Action.

Update:

I deleted the file and it does not reappear. So it’s possible that this file was deleted months ago and the GitHub push to Azure pushes all files up, but does not first delete all files to remove anything that has been deleted.

It was not in the production slot so a swap did not copy it across.

I am not answering this because, while I found a solution, I am hoping someone can post an authoritative answer.