Examine source code of Reddit Rainbow

{
  "manifest_version": 3,
  "name": "Reddit Rainbow",
  "browser_specific_settings": {
    "gecko": {
      "id": "@reddit-rainbow.padd_",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "version": "0.8.6",
  "description": "Improve nested comments with rainbow colors for better readability and highlight comments from the original poster (OP).",
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.reddit.com/r/*/comments/*"
      ],
      "js": [
        "background.js"
      ],
      "css": [
        "css/styles.css"
      ],
      "run_at": "document_end"
    }
  ],
  "action": {
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "96": "icons/icon-96.png"
    },
    "default_title": "Reddit Rainbow",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  }
}