Examine source code of Page Text Editor

{
  "name": "Page Text Editor",
  "description": "Adds a browser action icon to the toolbar. Click the button to choose a beast. The active tab's body content is then replaced with a picture of the chosen beast. See https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Examples#beastify",
  "manifest_version": 2,
  "version": "2.3",
  "homepage_url": "https://github.com/raymond-1227/PTE",
  "icons": {
    "48": "icons/pte-48.png",
    "96": "icons/pte-96.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/pte-inactive-32.png",
    "default_title": "Edit texts on screen",
    "default_popup": "popup/popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "raymond.hsu1227@gmail.com",
      "strict_min_version": "79.0"
    }
  }
}