Examine source code of ING autofill

{
  "$schema": "https://json.schemastore.org/chrome-manifest",
  "name": "ING autofill",
  "description": "Make password managers autofill work on the ING bank's website.",
  "homepage_url": "https://github.com/xxczaki/ing-autofill",
  "version": "0.2.1",
  "manifest_version": 3,
  "content_scripts": [
    {
      "run_at": "document_end",
      "js": [
        "build/main.js"
      ],
      "matches": [
        "https://login.ingbank.pl/*"
      ]
    }
  ],
  "icons": {
    "16": "icons/16.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "ing-autofill@parsify"
    }
  }
}