babel/packages/babel-plugin-proposal-private-methods/test/fixtures/private-static-method/async/input.js

class Cl {
  static async #privateStaticMethod() {
    return 2;
  }

  test() {
    return Cl.#privateStaticMethod();
  }
}

return new Cl().test().then(val => {
  expect(val).toBe(2);
});