When using fetch URIs with `"extract":true` we look for known file extensions, which doesn't play nice with urls with query string params.
The workaround is:
> The "output_file" field is useful here for cases where the URI ends with query parameters, since these will otherwise end up in the file copied to the sandbox and will subsequently fail to be recognized as archives.
The mearathon documentation is missing this property, which leads to confusion.
Edit: I realise that was the old documentation, and the new documentation does have outputFile: https://mesosphere.github.io/marathon/api-console/index.html
Some of the docs however still uses the uris api: https://mesosphere.github.io/marathon/docs/application-basics.html
(as well as the marathon new app UI)