Examine source code of Minimalist Twitter Theme

{
  "manifest_version": 2,
  "name": "Minimalist Twitter Theme",
  "version": "1.0",
  "description": "A simple, minimal theme for Twitter.",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png",
    "default_title": "Minimalist Twitter Theme"
  },
  "permissions": [
    "activeTab",
    "https://twitter.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://twitter.com/*"
      ],
      "css": [
        "content.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8f63ae5e-96d5-408c-9e74-d5140d4c069a}"
    }
  }
}