Examine source code of Steam age bypass

{
  "manifest_version": 2,
  "name": "Steam age bypass",
  "version": "1.1",
  "description": "Sets the age on the Steam age verification page automatically and presses View page for you.",
  "icons": {
    "128": "icons/steam.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "steam-age-bypass@addons",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://store.steampowered.com/agecheck/app/*",
        "*://store.steampowered.com/agecheck/bundle/*",
        "*://store.steampowered.com/agecheck/sub/*"
      ],
      "js": [
        "script.js"
      ],
      "run_at": "document_end"
    }
  ]
}