Examine source code of Focus Bubble

{
  "manifest_version": 2,
  "name": "Focus Bubble",
  "version": "1.0",
  "description": "Stay focused while browsing! Right-click to create a focus bubble that highlights a webpage area and blurs the rest. Toggle via toolbar and customize in a sleek settings page.",
  "permissions": [
    "activeTab",
    "storage",
    "contextMenus",
    "browserAction",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": {
      "48": "icon.png"
    },
    "default_title": "Toggle Focus Bubble"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4132f36a-71ab-45cf-98bc-092e5224bf9a}"
    }
  }
}