Examine source code of Form Filler

{
  "manifest_version": 2,
  "name": "FormFiller",
  "version": "1.0",
  "description": "Auto-fill repeated form data from saved profiles. Create, edit, and manage profiles in the popup.",
  "permissions": [
    "storage",
    "activeTab"
  ],
  "icons": {
    "48": "glyphs/ffil-48.png",
    "96": "glyphs/ffil-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "inject/injector.js"
      ],
      "css": [
        "inject/injector.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "jcmcrea2012p@outlook.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "browser_action": {
    "default_title": "FormFiller",
    "default_popup": "profile/profilePanel.html",
    "default_icon": {
      "48": "glyphs/ffil-48.png",
      "96": "glyphs/ffil-96.png"
    }
  }
}