Examine source code of Web Positiviser

{
  "manifest_version": 2,
  "name": "Web Positiviser",
  "version": "0.1.9",
  "description": "Make your web more positive by using sentiment analysis to reduce negative content visibility.",
  "browser_action": {
    "default_icon": "images/icon.png",
    "default_title": "Web Positiviser",
    "default_popup": "popup.html"
  },
  "icons": {
    "128": "images/icon.png"
  },
  "permissions": [
    "storage",
    "tabs",
    "http://localhost/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "run_at": "document_idle",
      "all_frames": false
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "negativitybalancer@artdgn.github.com"
    }
  }
}