structure of AJV standalone code generation code formats

https://ajv.js.org/standalone.html#configuration-and-limitations

In the following given example of the link above:

import myFormats from "./my-formats"
import Ajv, {_} from "ajv"

const ajv = new Ajv({
  formats: myFormats,
  code: {
    source: true,
    formats: _`require("./my-formats")`,
  },
})

If you only use formats from [ajv-formats](https://github.com/ajv-validator/ajv-formats) this option will be set by this package automatically.

There is no further details on how the “./my-formats” file must be structured.

Can someone link to official documentation that explains how the "./my-formats" must be structured?