Examine source code of Over 18 Cookie

{
  "manifest_version": 2,
  "name": "Over 18 Cookie",
  "version": "0.2.0",
  "description": "Set the over18 cookie automatically so you can skip Reddit's age gate.",
  "developer": {
    "name": "Eric King",
    "url": "https://webdeveric.com/"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "over18-cookie@webdeveric.com"
    }
  },
  "incognito": "spanning",
  "permissions": [
    "*://*.reddit.com/*",
    "cookies",
    "privacy"
  ],
  "background": {
    "page": "background.html"
  }
}