Examine source code of WowheadPains

{
  "manifest_version": 3,
  "name": "WowheadPains",
  "description": "Shrinks the side margin areas of wowhead to fill the screen content more. This is not an adblocker.",
  "version": "1.2",
  "icons": {
    "16": "WHPicon_small.png",
    "48": "WHPicon_medium.png",
    "128": "WHPicon_large.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.wowhead.com/*"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{cc5e8439-939f-4239-ac33-f86fc8584032}"
    }
  }
}