Examine source code of Bar Breaker

{
  "manifest_version": 2,
  "name": "Bar Breaker",
  "description": "Hides fixed headers and footers on pages you visit.",
  "version": "0.4.6",
  "applications": {
    "gecko": {
      "id": "bar-breaker@ris58h"
    }
  },
  "permissions": [
    "storage"
  ],
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "options_ui": {
    "page": "options/options.html"
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    },
    "default_title": "Bar Breaker"
  },
  "commands": {
    "toggle-enabled": {
      "description": "Toggle Bar Breaker on the current page"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "settings/settings.js",
        "content.js"
      ],
      "css": [
        "content.css"
      ]
    }
  ],
  "web_accessible_resources": [
    "settings/settings.json"
  ]
}