Sets the countries the site's project tracks besides its primary market, and returns the new list. Send the complete list you want: the call adds and deletes prompts to match it.

• Adding a country copies every primary-market prompt into it. Each country then has its own prompts and its own prompt limit.
• Removing a country deletes all of its prompts and their history. This can't be undone through the API.
• An empty list removes every additional country.

The plan's country limit counts the primary market plus the additional countries.

{
  "additional_geos": [
    "GB"
  ]
}

{
  "additional_geos": [
    "GB"
  ]
}