Missing schema in fetcher_configuration

This might be useful: https://www.drupal.org/project/svg_image/issues/3291801 🐛 Extend config schema instead of overriding it Fixed
and: https://drupal.stackexchange.com/questions/288586/how-do-i-extend-the-sc...

Basically you are just adding

    headers:
      type: textarea

to feeds.schema.yml Fetcher configurations right?

# Fetcher configurations.
feeds.fetcher.http:
  type: mapping
  label: 'HTTP fetcher settings'
  mapping:
    auto_detect_feeds:
      type: boolean
    use_pubsubhubbub:
      type: boolean
    always_download:
      type: boolean
    fallback_hub:
      type: string
    request_timeout:
      type: integer