Examine source code of Old Google Sheets Icons

{
  "manifest_version": 3,
  "name": "Old Google Sheets Icons",
  "version": "1",
  "description": "Replaces the new Google Sheets icons 🤮 with the previous ones :3",
  "browser_specific_settings": {
    "gecko": {
      "id": "oldgooglesheetsicons@avery",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://docs.google.com/spreadsheets/*"
      ],
      "css": [
        "styles.css"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "icon.png",
        "favicon.png"
      ],
      "matches": [
        "*://docs.google.com/*"
      ]
    }
  ]
}