@uigstudio/strapi-plugin-custom-fields/admin/src/pages/App/index.js

This plugin add custom fields

/**
 *
 * This component is the skeleton around the actual pages, and should only
 * contain code that should be seen on all pages. (e.g. navigation bar)
 *
 */

import React from 'react';
import {Route, Switch} from 'react-router-dom';
import {NotFound} from '@strapi/helper-plugin';
import pluginId from '../../pluginId';
import HomePage from '../HomePage';

const App = () => {
    return (
        <div>
            <Switch>
                <Route path={`/plugins/${pluginId}`} component={HomePage} exact />
                <Route component={NotFound} />
            </Switch>
        </div>
    );
};

export default App;