Examine source code of Super Form Filler

{
  "manifest_version": 3,
  "name": "Super Form Filler",
  "version": "1.0.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "super-form-filler@extensions.org",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "description": "Save form data on any website and refill it instantly with a single click or keyboard shortcut.",
  "permissions": [
    "storage",
    "activeTab",
    "contextMenus",
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background/background.js"
    ]
  },
  "action": {
    "default_popup": "popup/popup.html",
    "default_icon": "icons/icon.svg"
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content/filler.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "commands": {
    "fill_form": {
      "suggested_key": {
        "default": "Ctrl+Shift+F",
        "mac": "Command+Shift+F"
      },
      "description": "Fill the best matching form set"
    },
    "save_form": {
      "suggested_key": {
        "default": "Ctrl+Shift+S",
        "mac": "Command+Shift+S"
      },
      "description": "Quickly save current form fields"
    }
  },
  "icons": {
    "16": "icons/icon.svg",
    "32": "icons/icon.svg",
    "48": "icons/icon.svg",
    "128": "icons/icon.svg"
  }
}