Examine source code of Edit

{
  "manifest_version": 2,
  "name": "Edit",
  "version": "1.0.7",
  "description": "Toggle any webpage into an editable document with one click.",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "overlay/content.js"
      ],
      "css": [
        "overlay/mode.css"
      ]
    }
  ],
  "permissions": [
    "activeTab",
    "storage"
  ],
  "icons": {
    "16": "icons/edit-mode-16.png",
    "48": "icons/edit-mode-48.png",
    "128": "icons/edit-mode-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "utrac5945@gmail.com",
      "strict_min_version": "69.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "description": "Edit collects no data. Page editing state is stored locally only."
      }
    }
  },
  "browser_action": {
    "default_title": "Edit — Toggle Edit Mode",
    "default_icon": {
      "16": "icons/edit-mode-16.png",
      "48": "icons/edit-mode-48.png",
      "128": "icons/edit-mode-128.png"
    }
  },
  "background": {
    "scripts": [
      "toggle/state.js"
    ],
    "persistent": false
  }
}