{
  "@context": {
    "@vocab": "http://example.orb/vocab/",
    "at": {"@id": "@"},
    "foo.bar": {"@id": "@foo.bar"},
    "ignoreMe": {"@id": "@ignoreMe"}
  },
  "at": "allowed",
  "foo.bar": "allowed",
  "ignoreMe": "resolves to @vocab"
}