ProjectLighthouse/ProjectLighthouse/Serialization/XmlOutputFormatter.cs

using Microsoft.AspNetCore.Mvc.Formatters;

namespace LBPUnion.ProjectLighthouse.Serialization
{
    public class XmlOutputFormatter : StringOutputFormatter
    {
        public XmlOutputFormatter()
        {
            this.SupportedMediaTypes.Add("text/xml");
            this.SupportedMediaTypes.Add("application/xml");
        }
    }
}