How to read jest config values within test?

jest allows you to set global configuration values using either package.json, CLI options or a jest.config.js file.

You can set few config values in your tests e.g.

jest.setTimeout(10000000)

But I couldn't find a way to read config values, e.g.

const initialTimeout = jest.testTimeout // this is undefined
jest.setTimeout(10000000)
// do something that takes unusually long time
jest.setTimeout(initialTimeout)

So how can you read currently set global configuration values within a test?