Mailspring/app/internal_packages_disabled/plugins/lib/main.jsx

import { PreferencesUIStore } from 'mailspring-exports';
import PluginsView from './preferences-plugins';

export function activate() {
  this.preferencesTab = new PreferencesUIStore.TabItem({
    tabId: 'Plugins',
    displayName: 'Plugins',
    componentClassFn: () => PluginsView,
  });

  PreferencesUIStore.registerPreferencesTab(this.preferencesTab);
}

export function deactivate() {
  PreferencesUIStore.unregisterPreferencesTab(this.preferencesTab.sectionId);
}