Examine source code of linkfree

{
  "manifest_version": 2,
  "name": "linkfree",
  "description": "Set yourself free from remembering long, frequently-used links forever.",
  "version": "1.0.0",
  "author": "Pavitra Golchha",
  "icons": {
    "64": "icons/icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "linkfree.addon@pavi2410.me"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "activeTab",
    "contextMenus",
    "bookmarks"
  ]
}