Examine source code of Brain Tool

{
  "manifest_version": 2,
  "name": "Brain Tool",
  "description": "BrainTool is the best Bookmark and Tabs Manager for your online life.",
  "default_locale": "en",
  "version": "1.2.6",
  "permissions": [
    "tabs",
    "storage",
    "webNavigation",
    "bookmarks"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://BrainTool.org/versions/*"
      ],
      "run_at": "document_idle",
      "js": [
        "btContentScript.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": {
      "16": "images/BrainTool16.png",
      "32": "images/BrainTool32.png",
      "48": "images/BrainTool48.png",
      "128": "images/BrainTool128.png"
    },
    "default_title": "BrainTool!",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "images/BrainTool16.png",
    "32": "images/BrainTool32.png",
    "48": "images/BrainTool48.png",
    "128": "images/BrainTool128.png"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Alt+B"
      }
    }
  },
  "web_accessible_resources": [
    "images/BrainTool16.png",
    "images/BrainTool32.png",
    "images/BrainTool48.png",
    "images/BrainTool128.png",
    "popup.html",
    "btContentScript.js",
    "sidePanel.html"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{56e5ce3e-542a-4744-b716-7da397cb01fd}"
    }
  }
}