Examine source code of Pretty Good Bookmarks

{
  "name": "__MSG_extName__",
  "description": "__MSG_extDescription__",
  "default_locale": "en",
  "version": "1.1",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "activeTab",
    "contextMenus",
    "tabs"
  ],
  "browser_action": {
    "default_title": "__MSG_defaultTitle__",
    "default_icon": "pgb.png"
  },
  "manifest_version": 2
}