In /grafana/public/app/app.ts we see the following imports:
import 'whatwg-fetch'; // fetch polyfill needed for PhantomJs rendering
import 'abortcontroller-polyfill/dist/polyfill-patch-fetch'; // fetch polyfill needed for PhantomJs rendering
Looking at these lines and the comments therefore one can come to conclusion that those two imports are no longer necessary since PhantomJs is long gone from grafana.
I spoke to the Grafana team about this and they agree: these imports, and some additional polyfills in several tests, can probably go. I’ll make a PR unless you wanted to