Examine source code of Remove Asana Warning

{
  "manifest_version": 2,
  "name": "Remove Asana Warning",
  "description": "this will remove that ugly yellow header from asana",
  "version": "1.1resigned1",
  "browser_action": {
    "default_icon": "RAWLogo.png",
    "default_popup": "devinfo.html"
  },
  "content_scripts": [
    {
      "css": [
        "a.css"
      ],
      "js": [
        "content.js"
      ],
      "matches": [
        "https://app.asana.com/*"
      ]
    }
  ],
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{41454404-bc08-4372-9418-0bc3a12ac1ad}"
    }
  }
}