Examine source code of webmailbox

{
  "name": "webmailboxes",
  "description": "See logged-in webmail mailbox figures at a glance",
  "version": "2.0",
  "permissions": [
    "<all_urls>",
    "tabs"
  ],
  "background": {
    "scripts": [
      "background.js?0"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://outlook.live.com/*"
      ],
      "js": [
        "extra/content_common.js?0",
        "content_outlook.js?0"
      ]
    },
    {
      "matches": [
        "*://mail.google.com/*"
      ],
      "js": [
        "extra/content_common.js?0",
        "content_gmail.js?0"
      ]
    }
  ],
  "web_accessible_resources": [
    "gpl-1.0.txt?0",
    "popup.html?0",
    "page.html?0"
  ],
  "browser_action": {
    "default_icon": "default-64.png",
    "default_title": "webmailboxes"
  },
  "incognito": "spanning",
  "options_ui": {
    "page": "./options.html"
  },
  "manifest_version": 2
}