Examine source code of Subwatch

{
  "manifest_version": 2,
  "name": "subwatch",
  "description": "Turn subscription chaos into financial harmony",
  "version": "1.1.0",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "background",
    "cookies",
    "storage",
    "unlimitedStorage",
    "alarms",
    "notifications",
    "<all_urls>"
  ],
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAww1u4MGr4YRrwAO4S9jamyxDWfHK90derpwHLPEL7XGvWBqIFimEDdA5YK+5YwgjysBrWkp8gGA8pvWjZu9pg/7Si582/o87Wk9tk+N6r0ERrnjwo65Dbe7pluGEQYXLVRkESKBGun6Nua4fwBrBy1/GhmbLT6Nkp5raavUXTpCn3ROcy1biGQX0ezMDJQryXJp+ulS4Sei1iWPqK29WauNm+IZHQWg9a3on1G3KprJnaoRPtsA5LsYxVJ9x+6FjDJ3gTuLnYnym5e8/QdzV73Jk1M7pzEf2NqSYe/3MxNOPo0cOuBHluFQpwt285EZmsYwfhGBRtdMa1i2+dhJLowIDAQAB",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Default Popup Title",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.google.com/*"
      ],
      "run_at": "document_start",
      "js": [
        "content-scripts/content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{3ce15aea-db67-4b87-ad71-9ba408777b67}"
    }
  }
}