Central Feeds Service has injected some checks into our build to ensure we are only using package upstreams. It does this by validating that nuget.config files exist for each .csproj file and only include nonpublic feeds.
The exhaust of this repository that we deploy is built under bxl.exe which doesn't use .csproj files. So by and large this configuration is correct by construction. Any Microsoft internal build uses the internal feed while public builds use public feeds.
There are a handful of projects with checked in .csproj files. We want those files to be buildable both internally and externally. So pinning them to an internal only nuget.config file would not be appropriate. Ignore these CFS validations for the time being until they work out their policies for open sourced repos.
Michael Pysson