During one of my actions I used to get packages in my repo with something like (I left out the exact query for brevity):

query { 
  repository(owner:"ModelingValueGroup", name:"buildTools") {
    registryPackages
  }
}

but now this code suddenly fails with

Field 'registryPackages' doesn't exist on type 'Repository'

the API docs say it exists: https://developer.github.com/v4/object/repository/

What happened?