For instance, V8 would like to validate cr-buildbucket.cfg to ensure that

  mixins: "multibot"

is never combined with any platform mixins:

  mixins: "linux64"
  mixins: "win64"
  mixins: "mac64"

because it already includes "linux64" and should someone try to add this mixin with "win64" or "mac64", it will cause Buildbucket to silently fail to schedule builds because we don't have non-Linux multibot machines in our pool.

From config service, we'd love some kind of API to generate a JSON representation of the same config such that we can parse it and add custom rules. Alternative solution would be to keep a copy of the generated Python protobuf lib, but is likely to get out of sync at some point.