Definir o reagir de agente de usuário personalizado

let headers = new Headers({
    "Accept"       : "application/json",
    "Content-Type" : "application/json",
    "User-Agent"   : "MY-UA-STRING"
});

fetch(url, {
    method  : 'GET', 
    headers : headers 
    // ... etc
}).then( ...
Xanthous Xenomorph