Ghost/ghost/admin/app/controllers/explore.js

import Controller from '@ember/controller';
import {action} from '@ember/object';
import {inject as service} from '@ember/service';

export default class ExploreController extends Controller {
    @service ghostPaths;

    get apiUrl() {
        const origin = new URL(window.location.origin);
        const subdir = this.ghostPaths.subdir;
        // We want the API URL without protocol
        let url = this.ghostPaths.url.join(origin.host, subdir);

        return url.replace(/\/$/, '');
    }

    get exploreCredentials() {
        const explore = this.model.findBy('slug', 'ghost-explore');
        const adminKey = explore.adminKey;

        return adminKey.secret;
    }

    @action
    submitExploreSite() {
        const token = this.exploreCredentials;
        const apiUrl = this.apiUrl;

        // Ghost Explore URL to submit a new site
        const destination = new URL('https://ghost.org/explore/submit');
        const query = new URLSearchParams();

        query.append('token', token);
        query.append('url', apiUrl);

        destination.search = query;

        window.location = destination.toString();
    }
}