curl --request GET \
  --url https://discord.com/api/v10/applications/{application_id}/guilds/{guild_id}/commands/{command_id}/permissions \
  --header 'Authorization: <api-key>'

{
  "id": "<string>",
  "application_id": "<string>",
  "guild_id": "<string>",
  "permissions": [
    {
      "id": "<string>",
      "type": 123,
      "permission": true
    }
  ]
}