Examine source code of Page Greyscale Toggle

{
  "manifest_version": 3,
  "name": "Page Greyscale Toggle",
  "version": "1.0",
  "description": "Page Greyscale Toggle: View page in greyscale.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": "page_greyscale_toggle.png"
  },
  "icons": {
    "128": "page_greyscale_toggle.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "jasonwalsh3169@outlook.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}